Question

In ADEF, the measure of ZF=90°, the measure of ZD=69°, and FD = 64 feet. Find

the length of DE to the nearest tenth of a foot.

Answer 1

9514 1404 393

Answer:

178.6 ft

Explanation:

The definitions of the trig functions tell you ...

Cos = Adjacent/Hypotenuse

cos(69°) = FD/DE

DE = FD/cos(69°) ≈ (64 ft)/0.3584

DE ≈ 178.6 ft