Unit 7 Lesson 4: The Midpoint Formula

Question 1

average

Answer 1

the total of all the values divided by the number of values

Question 2

midpoint

Answer 2

a point that is the exact middle of a line segment

Question 3

The midpoint of a segment of length 23.4 divides the segment into two segments so that each have what length?

Answer 3

The midpoint divides the segment into congruent segments of length 23.4÷2=11.7
.

Question 3

A line segment has endpoints M=−23.7
and N=15.6. What is the midpoint of segment MN
?

Answer 3

The midpoint of segment MN
is −23.7+15.6 / 2 = −8.1/2 = −4.05
.

Question 4

Find the midpoint M of the line segment with endpoints P(2.8,1.1) and Q( −3.4
,5.7).

Answer 4

The midpoint of segment PQ is (−0.3,3.4)
.

Question 5

When using the midpoint formula, does it matter which endpoint has coordinates (x1,y1)
and which has coordinates (x2,y2)
? Why or why not?

Answer 5

It does not matter how you assign coordinates of the endpoints to (x1,y1)
and (x2,y2)
. In the midpoint formula, the x-coordinates are added, as are the y-coordinates, before dividing by 2, and addition is commutative. That is, changing the order of addends does not change the sum.