Answer:
x = 20 degrees.
Explanation:
cos40∘=sin(x+30∘)
sin (x + 30) = 0.766
x + 30 = arcsin 0.766 = 50
x = 50 - 30 = 20.
x = 20
cos(angle) = sin(complement of angle) , then
cos40 = sin(90 - 40) = sin50 , then
sin(x + 30) = sin50 , that is
x + 30 = 50 ( subtract 30 from both sides )
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