Answer:
x ≈ 39.2°
Step-by-step explanation:
Given
324 = 1409 - 1400 cos x ( subtract 1409 from both sides )
-1085 = - 1400 cos x ( divide both sides by - 1400 )
0.775 = cos x, thus
x = [tex]cos^{-1}[/tex] (0.775) ≈ 39.2° ( to 1 dec. place )