In the triangle ABC, the angle C is 90 degrees, AB = 15, cosA = √21 / 2. Find AC.

univerkov | May 16, 2021 | education

Cosine ∠A is the quotient of dividing the length of the AC leg, which is one of the sides of this angle, that is, adjacent to it, by the length of the hypotenuse AB rectangular Δ ABC.

Cosine ∠A = AC: AB = √21 / 2.

AC = √21 / 2 x 15 = 7.5√21 units of measurement.

Answer: the length of the speaker is 7.5√21 units.

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