High School Math : Midpoint and Distance Formulas

Study concepts, example questions & explanations for High School Math

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Example Questions

Example Question #1 : How To Find The Midpoint Of A Line Segment

What would be the midpoint of a line segment with endpoints at \displaystyle (0,1) and \displaystyle (5,7)?

Possible Answers:

\displaystyle (5,6)

\displaystyle (\frac{5}{2},\frac{9}{2})

\displaystyle (\frac{5}{2},4)

\displaystyle (1,1)

\displaystyle (\frac{5}{2},\frac{5}{2})

Correct answer:

\displaystyle (\frac{5}{2},4)

Explanation:

The midpoint of a line segment is halfway between the two \displaystyle \small x values and halfway between the two \displaystyle \small y values.

Mathematically, that would be the average of each coordinate: \displaystyle (\frac{x_2+x_1}{2},\frac{y_2+y_1}{2}).

Plug in the \displaystyle (x,y) values from the given points and solve.

\displaystyle (\frac{5+0}{2},\frac{7+1}{2})

\displaystyle (\frac{5}{2},\frac{8}{2})

We can simplify the fraction to give our final answer.

\displaystyle (\frac{5}{2},4)

Example Question #2 : Lines

What would be the midpoint of a line segment with endpoints at \displaystyle (1,6) and \displaystyle (9,9)?

Possible Answers:

\displaystyle (0,0)

\displaystyle (5,7.5)

\displaystyle (2.5,7.5)

\displaystyle (5,7)

\displaystyle (4.5,4.5)

Correct answer:

\displaystyle (5,7.5)

Explanation:

The midpoint of a line segment is halfway between the two \displaystyle \small x values and halfway between the two \displaystyle \small y values.

Mathematically, that would be the average of each coordinate: \displaystyle (\frac{x_2+x_1}{2},\frac{y_2+y_1}{2}).

Plug in the \displaystyle (x,y) values from the given points and solve.

\displaystyle (\frac{9+1}{2},\frac{9+6}{2})

\displaystyle (\frac{10}{2},\frac{15}{2})

Simplify the fractions to get the final answer.

\displaystyle (5,7.5)

Example Question #2 : How To Find The Midpoint Of A Line Segment

If a line has a midpoint at \displaystyle (2,5), and the endpoints are \displaystyle (0,0) and \displaystyle (4,y), what is the value of \displaystyle y?

Possible Answers:

\displaystyle 5

\displaystyle 1

\displaystyle 10

\displaystyle 4

\displaystyle 2.5

Correct answer:

\displaystyle 10

Explanation:

The midpoint of a line segment is halfway between the two \displaystyle \small x values and halfway between the two \displaystyle \small y values.

Mathematically, that would be the average of the coordinates: \displaystyle (\frac{x_2+x_1}{2},\frac{y_2+y_1}{2}).

Plug in the \displaystyle (x,y) values from the given points.

\displaystyle (\frac{4+0}{2},\frac{y+0}{2})=(2,5)

Now we can solve for the missing value.

\displaystyle (\frac{4}{2},\frac{y}{2})=(2,5)

\displaystyle \frac{4}{2}=2

The \displaystyle \small x values reduce, so both \displaystyle \small x values equal \displaystyle \small 2. Now we need to create a new equation to solve for the \displaystyle \small y value.

\displaystyle \frac{y}{2}=5

Multiply both sides by \displaystyle 2 to solve.

\displaystyle (2)\frac{y}{2}=5(2)

\displaystyle y=10

Example Question #3 : How To Find The Midpoint Of A Line Segment

What is the midpoint of a line segment with endpoints \displaystyle (1,1) and \displaystyle (12,12)?

Possible Answers:

\displaystyle (11,-11)

\displaystyle (13,13)

\displaystyle (6,6)

\displaystyle (\frac{1}{2},\frac{3}{4})

\displaystyle (\frac{13}{2},\frac{13}{2})

Correct answer:

\displaystyle (\frac{13}{2},\frac{13}{2})

Explanation:

The midpoint formula is this: \displaystyle (\frac{x_2+x_1}{2},\frac{y_2+y_1}{2}).

Plug in the given values from our points and solve:

\displaystyle (\frac{x_2+x_1}{2},\frac{y_2+y_1}{2})

\displaystyle (\frac{12+1}{2},\frac{12+1}{2})

\displaystyle (\frac{13}{2},\frac{13}{2})

Example Question #1 : Coordinate Geometry

What is the midpoint of the line segment with endpoints at \displaystyle (6,3) and \displaystyle (9,2)?

Possible Answers:

\displaystyle (\frac{9}{2},\frac{5}{2})

\displaystyle (\frac{2}{15},\frac{2}{5})

\displaystyle (7,3)

\displaystyle (\frac{15}{2},\frac{5}{2})

\displaystyle (\frac{2}{3},\frac{5}{3})

Correct answer:

\displaystyle (\frac{15}{2},\frac{5}{2})

Explanation:

The midpoint formula is this: \displaystyle (\frac{x_2+x_1}{2},\frac{y_2+y_1}{2}).

Plug in the given values from our points and solve:

\displaystyle (\frac{x_2+x_1}{2},\frac{y_2+y_1}{2})

\displaystyle (\frac{9+6}{2},\frac{2+3}{2})

\displaystyle (\frac{15}{2},\frac{5}{2})

Example Question #2 : Algebra I

Find the midpoint between (4, 3) and (6, 9).

Possible Answers:

\displaystyle \left ( 0,6 \right )

\displaystyle \left ( 3,6 \right )

\displaystyle \left ( 6,5 \right )

\displaystyle \left ( 5,6 \right )

\displaystyle \left ( -5,6 \right )

Correct answer:

\displaystyle \left ( 5,6 \right )

Explanation:

Add up the \displaystyle x's and divide in half, which results in 5. Do the same to the \displaystyle y's and you get 6. Put the \displaystyle x and \displaystyle y in an ordered pair so that your answer is (5, 6). 

Example Question #2 : Coordinate Geometry

What is the midpoint of the line segment which connects \displaystyle (-6, 8) and \displaystyle (2, 12)

Possible Answers:

\displaystyle (-8, -4)

\displaystyle (-4, 20)

\displaystyle (2, 10)

\displaystyle (8, 4)

\displaystyle (-2, 10)

Correct answer:

\displaystyle (-2, 10)

Explanation:

To find the midpoint of a line segment, we find the average of the x and y coordinates of the endpoints. The average of two numbers is the sum of those numbers divided by \displaystyle 2. Thus, to find the x-coordinate of our midpoint, we find the average of \displaystyle -6 and \displaystyle 2, and we get \displaystyle (-6+2)/2=-4/2 = -2.

 

To find the y-coordinate of our midpoint, we find the average of \displaystyle 8 and \displaystyle 12, which is \displaystyle (8+12)/2=20/2 = 10.

Thus, our midpoint is \displaystyle (-2, 10).

Example Question #5 : How To Find The Midpoint Of A Line Segment

Find the midpoint of the line segment with end points \displaystyle (-2,3) and \displaystyle (-4,16).

Possible Answers:

\displaystyle (-6,19)

\displaystyle (6,-19)

\displaystyle (3,9.5)

\displaystyle (3,-9.5)

\displaystyle (-3,9.5)

Correct answer:

\displaystyle (-3,9.5)

Explanation:

To find the midpoint of a line segment, use the standard equation: 

\displaystyle (\frac{x_1+x_2}{2},\frac{y_1+y_2}{2})

Plugging in the given points:

\displaystyle (\frac{-2+-4}{2},\frac{3+16}{2})=(-3,9.5)

Example Question #8 : Coordinate Geometry

Find the midpoint of these two points:

\displaystyle (-2,13) and \displaystyle (4,-9)

Possible Answers:

\displaystyle (2,1)

\displaystyle (2,4)

\displaystyle (4,2)

\displaystyle (1,2)

\displaystyle (-1,2)

Correct answer:

\displaystyle (1,2)

Explanation:

The standard formula to find the midpoint of two points is \displaystyle (\frac{x_1+x_2}{2},\frac{y_1+y_2}{2}).

Plug in the given points to find the answer:

\displaystyle (\frac{-2+4}{2},\frac{13+(-9)}{2})=(\frac{2}{2},\frac{4}{2})=(1,2)

Example Question #2 : Algebra I

A line segment has endpoints at \displaystyle (2,3) and \displaystyle (-7,3). What is the midpoint of this segment?

Possible Answers:

\displaystyle (-4.5,0)

\displaystyle (9,3)

\displaystyle (-5,3)

\displaystyle (-2.5,3)

\displaystyle (-4.5,3)

Correct answer:

\displaystyle (-2.5,3)

Explanation:

My midpoint will be at the average of the \displaystyle x-values and the average of the \displaystyle y-values. Mathematically, \displaystyle (\frac{x_2+x_1}{2}, \frac{y_2+y_1}{2}).

Plug in our given values.

\displaystyle (\frac{x_2+x_1}{2}, \frac{y_2+y_1}{2})

\displaystyle (\frac{-7+2}{2}, \frac{3+3}{2})

\displaystyle (\frac{-5}{2}, \frac{6}{2})

\displaystyle (-2.5,3)

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