Question

If sina=4/5 find the cosa
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Answer 1

cos A = 3/5

Explanation:

sin A = 4/5

sin^2 A + cos^2 A = 1

(4/5)^2 + cos^2 A = 1

16/25 + cos^2 A = 1

cos^2 A = 9/25

cos A = 3/5