McGraw Hill Glencoe Geometry, 2012
MH
McGraw Hill Glencoe Geometry, 2012 View details
1. Geometric Mean
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Exercise 59 Page 545

Find the lengths of the sides of each triangle.

Graph:

Verification: See solution.

Practice makes perfect

Let's use the given coordinates to draw the original figure and its dilated image.

Let's use the coordinates of the vertices to find the lengths of the sides of each triangle.
Side Vertices Distance Formula Simplified
First Pair of Sides AC (- 3,1), ( 3,- 2) sqrt(( 3-(- 3))^2+( - 2-1)^2) sqrt(45)
DF ( - 1,1), (1,0) sqrt((1-( - 1))^2+( - 1)^2) sqrt(5)
Second Pair of Sides AB (- 3,1), ( 9,7) sqrt(( 9-(-3))^2+( 7-1)^2) sqrt(180)
DE ( - 1,1), ( 3,3) sqrt(( 3-( -1))^2+( 3- 1)^2) sqrt(20)
Third Pair of Sides CB ( 3,- 2), ( 9,7) sqrt(( 9- 3)^2+( 7-( - 2))^2) sqrt(117)
FE (1,0), ( 3,3) sqrt(( 3-1)^2+( 3- )^2) sqrt(13)

Now, we can find the ratios between the corresponding sides. AC/DF=sqrt(45)/sqrt(5) = 3 [1.2em] AB/DE=sqrt(180)/sqrt(20) = 3 [1.2em] CB/FE=sqrt(117)/sqrt(13) = 3 We can tell that these ratios are equivalent. Therefore, the corresponding side lengths of â–ł ABC and â–ł DEF are proportional. By the Side-Side-Side Similarity Theorem, we can conclude that â–ł ABC is similar to â–ł DEF. â–ł ABC ~ â–ł DEF Therefore, the dilation is a similarity transformation.