Intermediate Geometry : Lines

Study concepts, example questions & explanations for Intermediate Geometry

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Example Questions

Example Question #21 : Midpoint Formula

Find the midpoint of a line segment that has endpoints at \displaystyle \left(\frac{1}{2}, 5\right) and \displaystyle \left(-\frac{3}{2}, 1\right).

Possible Answers:

\displaystyle (-\frac{3}{4}, 6)

\displaystyle (-\frac{1}{2}, -\frac{1}{2})

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

\displaystyle (-\frac{1}{2}, 2)

Correct answer:

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

Explanation:

Recall the formula for finding a midpoint of a line segment:

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

The coordinates of the midpoint is just the average of the x-coordinates and the average of the y-coordinates.

Plug in the given points to find the midpoint of the line segment.

\displaystyle \text{Midpoint}=(\frac{\frac{1}{2}-\frac{3}{2}}{2}, \frac{5+1}{2})=(-\frac{1}{2}, 3)

Example Question #21 : How To Find The Midpoint Of A Line Segment

Find the midpoint of a line segment that has endpoints at \displaystyle (9, 120) and \displaystyle (-24, 2).

Possible Answers:

\displaystyle (\frac{15}{2}, 61)

\displaystyle (-\frac{15}{2}, 59)

\displaystyle (-\frac{33}{2}, 60)

\displaystyle (-\frac{15}{2}, 61)

Correct answer:

\displaystyle (-\frac{15}{2}, 61)

Explanation:

Recall how to find the midpoint of a line segment with endpoints at \displaystyle (x_1, y_1) and \displaystyle (x_2, y_2):

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

\displaystyle \text{Midpoint}=(\frac{9+(-24)}{2}, \frac{120+2}{2})=(-\frac{15}{2}, 61)

Example Question #21 : Lines

Find the midpoint of a line segment that has endpoints at \displaystyle (16, 7) and \displaystyle (8, 9).

Possible Answers:

\displaystyle (\frac{25}{2}, \frac{15}{2})

\displaystyle (1, 8)

\displaystyle (4, -1)

\displaystyle (12, 8)

Correct answer:

\displaystyle (12, 8)

Explanation:

Recall how to find the midpoint of a line segment with endpoints at \displaystyle (x_1, y_1) and \displaystyle (x_2, y_2):

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

\displaystyle \text{Midpoint}=(\frac{16+8}{2}, \frac{7+9}{2})=(12, 8)

Example Question #22 : How To Find The Midpoint Of A Line Segment

A line segment on the coordinate plane has its endpoints at \displaystyle (3.8, -1.7) and \displaystyle (9.2, 5.5).

True or false: Its midpoint is located at \displaystyle (6.5, 3.6).

Possible Answers:

False

True

Correct answer:

False

Explanation:

The midpoint of a line segment with endpoints \displaystyle (x_{1}, y_{1}) and \displaystyle (x_{2}, y_{2}) is located at \displaystyle \left ( \frac{x_{1}+x_{2}}{2} , \frac{y_{1}+ y_{2}}{2} \right )

Set \displaystyle x_{1}= 3.8, y_{1} =-1.7,x_{2} =9.2, y_{2}= 5.5, and evaluate both expressions:

\displaystyle \frac{x_{1}+x_{2}}{2}= \frac{3.8+9.2}{2} = \frac{13}{2} = 6.5

\displaystyle \frac{-1.7+5.5}{2} =\frac{3.8}{2} = 1.9

The midpoint is at \displaystyle (6.5, 1.9), so the statement is false.

Example Question #1306 : Intermediate Geometry

Find the midpoint between the points:

\displaystyle (0,4) and \displaystyle (2,8)

Possible Answers:

\displaystyle (0,0)

\displaystyle (1,6)

\displaystyle (1,1)

\displaystyle (1,7)

\displaystyle (2,4)

Correct answer:

\displaystyle (1,6)

Explanation:

The midpoint formula is

\displaystyle \left(\frac{x_{1}+x_{2}}{2},\frac{y_{1}+y_{2}}{2}\right)

So for our two points the equation is

\displaystyle \left(\frac{0+2}{2},\frac{4+8}{2}\right)

\displaystyle \left(\frac{2}{2},\frac{12}{2}\right)

\displaystyle (1,6)

Example Question #1311 : Intermediate Geometry

What is the midpoint between the two points:

\displaystyle (0,0) and \displaystyle (3,4)

Possible Answers:

\displaystyle (3,4)

\displaystyle (9,16)

\displaystyle (2,1.5)

\displaystyle (1.5,2)

\displaystyle (4,3)

Correct answer:

\displaystyle (1.5,2)

Explanation:

The midpoint formula is

\displaystyle \left(\frac{x_{1}+x_{2}}{2},\frac{y_{1}+y_{2}}{2}\right)

If we plug in our points we get

\displaystyle \left(\frac{0+3}{2},\frac{0+4}{2}\right)

\displaystyle \left(\frac{3}{2},\frac{4}{2}\right)

\displaystyle (1.5,2)

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

What is the midpoint between the two points:

\displaystyle (1,9) and \displaystyle (3, 5)

Possible Answers:

\displaystyle (1,9)

\displaystyle (7,2)

\displaystyle (2,7)

\displaystyle (3,4)

\displaystyle (2,5)

Correct answer:

\displaystyle (2,7)

Explanation:

The midpoint formula is

\displaystyle \left(\frac{x_{1}+x_{2}}{2},\frac{y_{1}+y_{2}}{2}\right)

So lets plug in our two points, that gives us

\displaystyle \left(\frac{1+3}{2},\frac{9+5}{2}\right)

\displaystyle \left(\frac{4}{2},\frac{14}{2}\right)

\displaystyle (2,7)

Example Question #21 : Lines

What is the midpoint between the two points:

\displaystyle (0,0) and \displaystyle (4,5)

Possible Answers:

\displaystyle (2,2)

\displaystyle (4,5)

\displaystyle (2,2.5)

\displaystyle (2,5)

\displaystyle (4,2.5)

Correct answer:

\displaystyle (2,2.5)

Explanation:

The equation to find the midpoint between two points is

\displaystyle \left(\frac{x_{1}+x_{2}}{2},\frac{y_{1}+y_{2}}{2}\right)

If we plug in our values of the two points we get

\displaystyle \left(\frac{0+4}{2},\frac{0+5}{2}\right)

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

\displaystyle (2,2.5)

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

One of the endpoints of a line is \displaystyle \small (8, -7) and the midpoint is \displaystyle \small (1, -3). What is the other endpoint?

Possible Answers:

\displaystyle \small (15, 1 )

\displaystyle \small (-6, 1)

\displaystyle \small (-6, -11)

\displaystyle \small (15, -11)

\displaystyle \small (3, -1)

Correct answer:

\displaystyle \small (-6, 1)

Explanation:

The midpoint's coordinates are the average of the endpoints'.

This means that the x-coordinates of the two endpoints have a mean of 1:

\displaystyle \small \frac{8+x }{2} = 1 multiply both sides by 2

\displaystyle \small 8 + x = 2 subtract 8

\displaystyle \small x = -6 this means the other endpoint's x-coordinate is -6

 

This also means that the y-coordinates of the two endpoints have a mean of -3:

\displaystyle \small \frac{-7+y}{2} = -3 multiply both sides by 2

\displaystyle \small -7 + y = -6 add 7 to both sides

\displaystyle \small y = 1

The coordinate pair that we're looking for is (-6, 1)

Example Question #1313 : Intermediate Geometry

The midpoint of a line is \displaystyle \small (9, 9) and one of the endpoints is \displaystyle \small (1, 17). What is the other endpoint?

Possible Answers:

\displaystyle \small (17, 25)

\displaystyle \small (-7, 25)

\displaystyle \small (8, -8)

\displaystyle \small (-7, 1 )

\displaystyle \small (17, 1)

Correct answer:

\displaystyle \small (17, 1)

Explanation:

The midpoint's coordinates are just the mean of the endpoints'.

This means that the mean of the two x-coordinates is 9:

\displaystyle \small \frac{x+ 1}{2} = 9 multiply both sides by 2

\displaystyle \small x + 1 = 18 subtract 1

\displaystyle \small x = 17

This also means that the mean of the two y-coordinates is 9:

\displaystyle \small \frac{y+17}{2} = 9 multiply both sides by 2

\displaystyle \small y + 17 = 18 subtract 17

\displaystyle \small y = 1

So the other endpoint we were solving for is \displaystyle \small (17, 1 )

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