ABC – right triangle;
Angle C = 90 °;
sin A = 0.8;
Find cos B.
We apply the formula: sin A = BC / AB.
Since cos B = BC / AB, then we get: sin A = BC / AB = cos B.
Hence, we obtain that cos B = sin A.
Substitute the known value sin A = 0.8 into the expression cos B = sin A and find cos B.
cos B = sin A = 0.8.
This means that cos B = 0.8.
Answer: cos B = 0.8.
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