Triangles - Math
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Points A and B lie on a circle centered at Z, where central angle <AZB measures 140°. What is the measure of angle <ZAB?
Points A and B lie on a circle centered at Z, where central angle <AZB measures 140°. What is the measure of angle <ZAB?
Because line segments ZA and ZB are radii of the circle, they must have the same length. That makes triangle ABZ an isosceles triangle, with <ZAB and <ZBA having the same measure. Because the three angles of a triangle must sum to 180°, you can express this in the equation:
140 + 2x = 180 --> 2x = 40 --> x = 20
Because line segments ZA and ZB are radii of the circle, they must have the same length. That makes triangle ABZ an isosceles triangle, with <ZAB and <ZBA having the same measure. Because the three angles of a triangle must sum to 180°, you can express this in the equation:
140 + 2x = 180 --> 2x = 40 --> x = 20
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In triangle ABC, Angle A = x degrees, Angle B = 2x degrees, and Angle C = 3x+30 degrees. How many degrees is Angle B?
In triangle ABC, Angle A = x degrees, Angle B = 2x degrees, and Angle C = 3x+30 degrees. How many degrees is Angle B?
Because the interior angles of a triangle add up to 180°, we can create an equation using the variables given in the problem: x+2x+(3x+30)=180. This simplifies to 6X+30=180. When we subtract 30 from both sides, we get 6x=150. Then, when we divide both sides by 6, we get x=25. Because Angle B=2x degrees, we multiply 25 times 2. Thus, Angle B is equal to 50°. If you got an answer of 25, you may have forgotten to multiply by 2. If you got 105, you may have found Angle C instead of Angle B.
Because the interior angles of a triangle add up to 180°, we can create an equation using the variables given in the problem: x+2x+(3x+30)=180. This simplifies to 6X+30=180. When we subtract 30 from both sides, we get 6x=150. Then, when we divide both sides by 6, we get x=25. Because Angle B=2x degrees, we multiply 25 times 2. Thus, Angle B is equal to 50°. If you got an answer of 25, you may have forgotten to multiply by 2. If you got 105, you may have found Angle C instead of Angle B.
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Triangle FGH has equal lengths for FG and GH; what is the measure of ∠F, if ∠G measures 40 degrees?
Triangle FGH has equal lengths for FG and GH; what is the measure of ∠F, if ∠G measures 40 degrees?
It's good to draw a diagram for this; we know that it's an isosceles triangle; remember that the angles of a triangle total 180 degrees.
Angle G for this triangle is the one angle that doesn't correspond to an equal side of the isosceles triangle (opposite side to the angle), so that means ∠F = ∠H, and that ∠F + ∠H + 40 = 180,
By substitution we find that ∠F * 2 = 140 and angle F = 70 degrees.
It's good to draw a diagram for this; we know that it's an isosceles triangle; remember that the angles of a triangle total 180 degrees.
Angle G for this triangle is the one angle that doesn't correspond to an equal side of the isosceles triangle (opposite side to the angle), so that means ∠F = ∠H, and that ∠F + ∠H + 40 = 180,
By substitution we find that ∠F * 2 = 140 and angle F = 70 degrees.
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The vertex angle of an isosceles triangle is
. What is the base angle?
The vertex angle of an isosceles triangle is . What is the base angle?
An isosceles triangle has two congruent base angles and one vertex angle. Each triangle contains
. Let
= base angle, so the equation becomes
. Solving for
gives 
An isosceles triangle has two congruent base angles and one vertex angle. Each triangle contains . Let
= base angle, so the equation becomes
. Solving for
gives
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In an isosceles triangle the base angle is five less than twice the vertex angle. What is the sum of the vertex angle and the base angle?
In an isosceles triangle the base angle is five less than twice the vertex angle. What is the sum of the vertex angle and the base angle?
Every triangle has 180 degrees. An isosceles triangle has one vertex angle and two congruent base angles.
Let
= the vertex angle
and
= base angle
So the equation to solve becomes

or

Thus the vertex angle is 38 and the base angle is 71 and their sum is 109.
Every triangle has 180 degrees. An isosceles triangle has one vertex angle and two congruent base angles.
Let = the vertex angle
and = base angle
So the equation to solve becomes
or
Thus the vertex angle is 38 and the base angle is 71 and their sum is 109.
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An isosceles triangle has a base angle that is six more than three times the vertex angle. What is the base angle?
An isosceles triangle has a base angle that is six more than three times the vertex angle. What is the base angle?
Every triangle has 180 degrees. An isosceles triangle has one vertex angle and two congruent base angles.
Let
= vertex angle and
= base angle.
Then the equation to solve becomes

or
.
Solving for
gives a vertex angle of 24 degrees and a base angle of 78 degrees.
Every triangle has 180 degrees. An isosceles triangle has one vertex angle and two congruent base angles.
Let = vertex angle and
= base angle.
Then the equation to solve becomes
or
.
Solving for gives a vertex angle of 24 degrees and a base angle of 78 degrees.
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The base angle of an isosceles triangle is thirteen more than three times the vertex angle. What is the difference between the vertex angle and the base angle?
The base angle of an isosceles triangle is thirteen more than three times the vertex angle. What is the difference between the vertex angle and the base angle?
Every triangle has
. An isosceles triangle has one vertex ange, and two congruent base angles.
Let
be the vertex angle and
be the base angle.
The equation to solve becomes
, since the base angle occurs twice.



Now we can solve for the vertex angle.

The difference between the vertex angle and the base angle is
.
Every triangle has . An isosceles triangle has one vertex ange, and two congruent base angles.
Let be the vertex angle and
be the base angle.
The equation to solve becomes , since the base angle occurs twice.
Now we can solve for the vertex angle.
The difference between the vertex angle and the base angle is .
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Sides
and
in this triangle are equal. What is the measure of
?

Sides and
in this triangle are equal. What is the measure of
?
This triangle has an angle of
. We also know it has another angle of
at
because the two sides are equal. Adding those two angles together gives us
total. Since a triangle has
total, we subtract 130 from 180 and get 50.
This triangle has an angle of . We also know it has another angle of
at
because the two sides are equal. Adding those two angles together gives us
total. Since a triangle has
total, we subtract 130 from 180 and get 50.
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An isoceles triangle has a base angle five more than twice the vertex angle. What is the difference between the base angle and the vertex angle?
An isoceles triangle has a base angle five more than twice the vertex angle. What is the difference between the base angle and the vertex angle?
A triangle has 180 degrees. An isoceles triangle has one vertex angle and two congruent base angles.
Let
= vertex angle and
= base angle
So the equation to solve becomes
or 
So the vertex angle is
and the base angle is
so the difference is 
A triangle has 180 degrees. An isoceles triangle has one vertex angle and two congruent base angles.
Let = vertex angle and
= base angle
So the equation to solve becomes
or
So the vertex angle is and the base angle is
so the difference is
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An isosceles triangle has a vertex angle that is twenty degrees more than twice the base angle. What is the sum of the vertex and base angles?
An isosceles triangle has a vertex angle that is twenty degrees more than twice the base angle. What is the sum of the vertex and base angles?
All triangles contain
degrees. An isosceles triangle has one vertex angle and two congruent base angles.
Let
and
.
So the equation to solve becomes
.
We get
and
, so the sum of the base and vertex angles is
.
All triangles contain degrees. An isosceles triangle has one vertex angle and two congruent base angles.
Let and
.
So the equation to solve becomes .
We get and
, so the sum of the base and vertex angles is
.
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If an isosceles triangle has an angle measuring greater than 100 degrees, and another angle with a measuring
degrees, which of the following is true?
If an isosceles triangle has an angle measuring greater than 100 degrees, and another angle with a measuring degrees, which of the following is true?
In order for a triangle to be an isosceles triangle, it must contain two equivalent angles and one angle that is different. Given that one angle is greater than 100 degrees:
Thus, the sum of the other two angles must be less than 80 degrees. If an angle is represented by
: 
In order for a triangle to be an isosceles triangle, it must contain two equivalent angles and one angle that is different. Given that one angle is greater than 100 degrees: Thus, the sum of the other two angles must be less than 80 degrees. If an angle is represented by
:
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An isoceles triangle has a base angle that is twice the vertex angle. What is the sum of the base and vertex angles?
An isoceles triangle has a base angle that is twice the vertex angle. What is the sum of the base and vertex angles?
All triangles have
degrees. An isoceles triangle has one vertex angle and two congruent base angles.
Let
vertex angle and
base angle.
So the equation to solve becomes:
or 
Thus
for the vertex angle and
for the base angle.
The sum of the vertex and one base angle is
.
All triangles have degrees. An isoceles triangle has one vertex angle and two congruent base angles.
Let vertex angle and
base angle.
So the equation to solve becomes:
or
Thus for the vertex angle and
for the base angle.
The sum of the vertex and one base angle is .
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An isoceles triangle has a vertex angle that is
degrees more than twice the base angle. What is the vertex angle?
An isoceles triangle has a vertex angle that is degrees more than twice the base angle. What is the vertex angle?
Every triangle has
degrees. An isoceles triangle has one vertex angle and two congruent base angles.
Let
base angle and
vertex angle.
So the equation to solve becomes
.


Thus the base angles are
and the vertex angle is
.
Every triangle has degrees. An isoceles triangle has one vertex angle and two congruent base angles.
Let base angle and
vertex angle.
So the equation to solve becomes .
Thus the base angles are and the vertex angle is
.
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An isoceles triangle has a base angle that is
degrees less than three times the vertex angle. What is the product of the vertex angle and the base angle?
An isoceles triangle has a base angle that is degrees less than three times the vertex angle. What is the product of the vertex angle and the base angle?
Every triangle has 180 degrees. An isoceles triangle has one vertex angle and two congruent base angles.
Let
vertex angle and
base angle.
Then the equation to solve becomes:
, or
.
Then the vertex angle is
, the base angle is
, and the product is
.
Every triangle has 180 degrees. An isoceles triangle has one vertex angle and two congruent base angles.
Let vertex angle and
base angle.
Then the equation to solve becomes:
, or
.
Then the vertex angle is , the base angle is
, and the product is
.
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An isoceles triangle has a base angle that is twice the vertex angle. What is the sum of one base angle and the vertex angle?
An isoceles triangle has a base angle that is twice the vertex angle. What is the sum of one base angle and the vertex angle?
Every triangle contains
degrees. An isoceles triangle has two congruent base angles and one vertex angle.
Let
the vertex angle and
the base angle
So the equation to solve becomes
or
and dividing by
gives
for the vertex angle and
for the base angle, so the sum is 
Every triangle contains degrees. An isoceles triangle has two congruent base angles and one vertex angle.
Let the vertex angle and
the base angle
So the equation to solve becomes or
and dividing by
gives
for the vertex angle and
for the base angle, so the sum is
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An isoceles triangle has a base angle that is five less than twice the vertex angle. What is the sum of the base and vertex angles?
An isoceles triangle has a base angle that is five less than twice the vertex angle. What is the sum of the base and vertex angles?
Each triangle has
degrees.
An isoceles triangle has two congruent base angles and one vertex angle.
Let
vertex angle and
base angle.
Then the equation to solve becomes
or
.
Add
to both sides to get
.
Divide both sides by
to get
vertex angle and
base angles, so the sum of the angles is
.
Each triangle has degrees.
An isoceles triangle has two congruent base angles and one vertex angle.
Let vertex angle and
base angle.
Then the equation to solve becomes or
.
Add to both sides to get
.
Divide both sides by to get
vertex angle and
base angles, so the sum of the angles is
.
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An isosceles triangle has a base of
and an area of
. What must be the height of this triangle?
An isosceles triangle has a base of and an area of
. What must be the height of this triangle?
.


.
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A triangle has a perimeter of
inches with one side of length
inches. If the remaining two sides have lengths in a ratio of
, what is length of the shortest side of the triangle?
A triangle has a perimeter of inches with one side of length
inches. If the remaining two sides have lengths in a ratio of
, what is length of the shortest side of the triangle?
The answer is
.
Since we know that the permieter is
inches and one side is
inches, it can be determined that the remaining two sides must combine to be
inches. The ratio of the remaining two sides is
which means 3 parts : 4 parts or 7 parts combined. We can then set up the equation
, and divide both sides by
which means
. The ratio of the remaining side lengths then becomes
or
. We now know the 3 side lengths are
.
is the shortest side and thus the answer.
The answer is .
Since we know that the permieter is inches and one side is
inches, it can be determined that the remaining two sides must combine to be
inches. The ratio of the remaining two sides is
which means 3 parts : 4 parts or 7 parts combined. We can then set up the equation
, and divide both sides by
which means
. The ratio of the remaining side lengths then becomes
or
. We now know the 3 side lengths are
.
is the shortest side and thus the answer.
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One side of an acute isosceles triangle is 15 feet. Another side is 5 feet. What is the perimeter of the triangle in feet?
One side of an acute isosceles triangle is 15 feet. Another side is 5 feet. What is the perimeter of the triangle in feet?
Because this is an acute isosceles triangle, the third side must be the same as the longer of the sides that you were given. To find the perimeter, multiply the longer side by 2 and add the shorter side.

Because this is an acute isosceles triangle, the third side must be the same as the longer of the sides that you were given. To find the perimeter, multiply the longer side by 2 and add the shorter side.
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The base of a right isosceles triangle is 8 inches. The hypotenuse is not the base. What is the area of the triangle in inches?
The base of a right isosceles triangle is 8 inches. The hypotenuse is not the base. What is the area of the triangle in inches?
To find the area of a triangle, multiply the base by the height, then divide by 2. Since the short legs of an isosceles triangle are the same length, we need to know only one to know the other. Since, a short side serves as the base of the triangle, the other short side tells us the height.

To find the area of a triangle, multiply the base by the height, then divide by 2. Since the short legs of an isosceles triangle are the same length, we need to know only one to know the other. Since, a short side serves as the base of the triangle, the other short side tells us the height.
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