
I guess you mean find sin A because I have no idea what B is
cos^2 + sin^2 = 1
0.8^2 + sin^2 = 1
sin^2 = 10.64 = 0.36
sin = +/ sqrt(0.36)posted by Damon

as shown above, sinA = ±0.6
or, you can see that if you draw a triangle, it is just a scaleddown 345 triangle. so if sinA = 4/5, cosA = 3/5.posted by Steve
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