The angle between the legs labeled [tex]x[/tex] and [tex]y[/tex] is complementary to the angle with measure 31 degrees, so that angle has measure 90 - 31 = 59 degrees. Then
[tex]\sin59^\circ=\dfrac{400}x\implies x=\dfrac{400}{\sin59^\circ}\approx466.7[/tex]
