1. EXAMPLE 1
Use similarity statements
In the diagram, ∆RST ~ ∆XYZ
a. List all pairs of congruent
angles.
b. Check that the ratios of
corresponding side lengths are equal. c.
Write the ratios of the corresponding side
lengths in a statement of proportionality.

2. EXAMPLE 1
Use similarity statements
SOLUTION a. R = ~ X, S Y T Z
and RS XY = 20 12 5 3 b. ; ST = 30 18 5 3 YZ ; TR ZX = 25 15 5 3
c. Because the ratios in part (b) are equal, YZ RS XY = ST TR ZX .

3. GUIDED PRACTICE
for Example 1
Given ∆ JKL ~ ∆ PQR, list all pairs of congruent angles. Write the ratios of the corresponding side lengths in a statement of proportionality. J = ~ P, K Q L R
and JK PQ KL QR LJ RP ;
ANSWER