Question 1180194
cos x^2+sin x^2=1, a useful identity.
so 0.25^2 +sin x^2=1
sin x^2=0.9375, since 0.25^2=0.0625
sin x=0.9682
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can check with tables
cos x=0.25 when x=75.52 degrees, using the inv cos function. Then with the degrees/radians, look at the sine function. 
sin 75.52 deg.=0.9682