Question

0 < x < 180, and sin 42 = cos x, what is the value of x?

Answer 1

Find the complement of 42 degrees:  subtract 42 degrees from 90 degrees.

Answer 2

Alright, lets get started.

There is identity which represents trigonometric functions in terms of their complements.

sin θ = cos (90 - θ)

Hence

`sin 42 = cos (90-42)`

So,
`x = 90 - 42`

So,

x = 48 : Answer

Hope it will help :)