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.

Respuesta :

9514 1404 393

Answer:

  178.6 ft

Step-by-step 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

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