# In triangle ABC, angle C is 90 degrees, BC = 8, sinA = 0.4. Find AB.

July 22, 2021 | education

| Given: right-angled triangle ABC;

angle C = 90;

sin A = 0.4;

BC = 8 centimeters;

Find: AB -?

Decision:

Consider a right-angled triangle ABC.

The sine of the angle in a right-angled triangle is equal to the ratio of the opposite leg to the hypotenuse. Consequently:

sin A = BC / AB;

AB = BC / sin A;

BC = sin A * AB

AB = 8: 0.4;

AB = 80: 4;

AB = 20 centimeters.

Answer: AB = 20 centimeters.

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