Question

Find X.

Round to the nearest tenth.
Z
20 ft
22ft
X
18 ft
Y
X= [?]°

Answer 1

X≈ 70.5°

Explanation:

Using the cosine rule in Δ XYZ

cos X =
`(y^2+z^2-x^2)/(2yz)`

with x = 22, y = 20, z = 18 , then

cos X =
`(202+18^2-22^2)/(2(20)(18))`

=
`(400+324-484)/(720)`

=
`(240)/(720)` , then

∠ X =
`cos^(-1)` (
`(240)/(720)` ) ≈ 70.5° ( to the nearest tenth )