All ISEE Upper Level Math Resources
Example Questions
Example Question #31 : Plane Geometry
Examine the above diagram. If , give in terms of .
The two marked angles are same-side exterior angles of parallel lines, which are supplementary - that is, their measures have sum 180. We can solve for in this equation:
Example Question #32 : Plane Geometry
Examine the above diagram. If , give in terms of .
The two marked angles are same-side interior angles of parallel lines, which are supplementary - that is, their measures have sum 180. We can solve for in this equation:
Example Question #4 : Lines
Examine the above diagram. What is ?
By angle addition,
Example Question #33 : Plane Geometry
Examine the above diagram. Which of the following statements must be true whether or not and are parallel?
Four statements can be eliminated by the various parallel theorems and postulates. Congruence of alternate interior angles or corresponding angles forces the lines to be parallel, so
and
.
Also, if same-side interior angles or same-side exterior angles are supplementary, the lines are parallel, so
and
.
However, whether or not since they are vertical angles, which are always congruent.
Example Question #34 : Plane Geometry
and are supplementary; and are complementary.
.
What is ?
Supplementary angles and complementary angles have measures totaling and , respectively.
, so its supplement has measure
, the complement of , has measure
Example Question #1 : How To Find An Angle
Note: Figure NOT drawn to scale.
In the above figure, and . Which of the following is equal to ?
and form a linear pair, so their angle measures total . Set up and solve the following equation:
Example Question #2 : How To Find An Angle
Two angles which form a linear pair have measures and . Which is the lesser of the measures (or the common measure) of the two angles?
Two angles that form a linear pair are supplementary - that is, they have measures that total . Therefore, we set and solve for in this equation:
The two angles have measure
and
is the lesser of the two measures and is the correct choice.
Example Question #6 : How To Find An Angle
Two vertical angles have measures and . Which is the lesser of the measures (or the common measure) of the two angles?
Two vertical angles - angles which share a vertex and whose union is a pair of lines - have the same measure. Therefore, we set up and solve the equation
Example Question #41 : Geometry
A line intersects parallel lines and . and are corresponding angles; and are same side interior angles.
Evaluate .
When a transversal such as crosses two parallel lines, two corresponding angles - angles in the same relative position to their respective lines - are congruent. Therefore,
Two same-side interior angles are supplementary - that is, their angle measures total 180 - so
We can solve this system by the substitution method as follows:
Backsolve:
, which is the correct response.
Example Question #3 : How To Find An Angle
Note: Figure NOT drawn to scale.
Refer to the above diagram. Give the measure of .
The top and bottom angles, being vertical angles - angles which share a vertex and whose union is a pair of lines - have the same measure, so
,
or, simplified,
The right and bottom angles form a linear pair, so their degree measures total 180. That is,
Substitute for :
The left and right angles, being vertical angles, have the same measure, so, since the right angle measures , this is also the measure of the left angle, .