Question

In ΔDEF, the measure of ∠F=90°, the measure of ∠E=41°, and FD = 79 feet. Find the length of DE to the nearest tenth of a foot.

Answer 1

120.4ft

Explanation:

Find the diagram in the attachment.

The triangle shown is a right angled triangle with the side DE as the hypotenuse, EF is adjacent side while DF is the opposite side.

To get DE, we will use the SOH CAH TOA trigonometry identity

Using CAH which is defined as:

Cos(theta) = Adjacent/Hypotenuse

Cos 79°= 23/Hypotenuse

Hypotenuse = 23/cos79°

Hypotenuse = 23/0.191

Hypotenuse = 120.4feet

DE = 120.4feet (to nearest tenth)