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Checkpoint Complete the following exercises.
1. Find the distance between (27, 3) and (5, 22).
2. The vertices of a triangle are T(2, 1), U(4, 6), and
V(7, 3). Classify nTUV as scalene, isosceles, or
equilateral.
THE MIDPOINT FORMULA
A line segment’s midpoint is from the
segment’s endpoints. The midpoint formula describes
the of a line segment joining A(x1 , y1 ) and
B(x2 , y2 ) as follows:
M 1 x1 1 x2 }
2 , y1 1 y2 }
2 2
In words, each coordinate of M is the of the
corresponding coordinates of A and B.
Example 3 Find the midpoint of a line segment
Find the midpoint of the line
segment joining (26, 5) and
(2, 23).
Let (x1 , y1 ) 5 (26, 5) and
(x2 , y2 ) 5 ( 2, 23).
1 x1 1 x2 }
2 , y1 1 y2 }
Midpoint M
(−6, 5)
2 2 5 1 , 2
5 ( , )
2
y
2
(2, −3)
Copyright © Holt McDougal. All rights reserved. Lesson 9.1 Algebra 2 Notetaking Guide 233
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