The value of A is 35.
The given expression is as follows:
sin A = cos (A + 20)
using trigonometric rule,
sin A = cos(90 - A)
Therefore,
cos (A + 20) = cos(90 - A)
divide both sides by cos
Hence,
A + 20 = 90 - A
A + A = 90 - 20
2A = 70
divide both sides by 2
A = 70 / 2
A = 35
Therefore, the value of A is 35.
learn more on trigonometry here: https://brainly.com/question/20593351
#SPJ1
