Question

Find Y.
Round to the nearest tenth.

Answer 1

Y ≈ 59.0°

Explanation:

Using the Cosine rule

cosY =
`(x^2+z^2-y^2)/(2xz)`

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

cosY =
`(22^2+18^2-20^2)/(2(22)(18))`

=
`(484+324-400)/(792)`

=
`(408)/(792)` , then

Y =
`cos^(-1)` (
`(408)/(792)` ) ≈ 59.0° ( to the nearest tenth )