In triangle ABC, angle C is 90, BC = 15, cos = 4/5. Find AC.

univerkov | September 25, 2021 | education

Given:

ABC – right-angled triangle;

Angle C – 90 degrees;

BC = 15;

cos A = 4/5;

Find AU.

Solution:

Cos A = AC / AB = BC / 25 = 4/5;

AC / 25 = 4/5;

Let’s multiply the equation cross by cross and find the BC side.

4 * 25 = 5 * AC;

AC = 4 * 25/5;

AC = 4 * 5;

AC = 20;

Answer: AC = 20.

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