Question

7. Triangles CDE and RST are similar triangles. What is
the length of side CD in triangle CDE?
R
40 ft.
32 ft.
20 ft.
T
S

Answer 1

Answer:

CD = 25 ft

Step-by-step explanation:

$\triangle CDE \sim \triangle RST$

$\therefore \frac{CD}{20}=\frac{40}{32}$

(Corresponding sides of similar triangles are in proportion)

$\therefore \frac{CD}{20}=\frac{5}{4}$

$\therefore CD = \frac{5}{\cancel 4}\times \cancel {20} \:\:\blue{\bold{5}}$

$\therefore CD = 5\times 5$

$\therefore CD = 25\: ft$

Answer 2

Answer:

CD = 25 ft

Step-by-step explanation:

Since the triangles are similar then the ratios of corresponding sides are equal, that is

$\frac{CD}{RS}$ = $\frac{CE}{RT}$ , substitute values

$\frac{CD}{20}$ = $\frac{40}{32}$  ( cross- multiply )

32CD = 800 ( divide both sides by 32 )

CD = 25