# In the triangle BAC, the angle C is 90. tg B = √21 / 2. Find cos B

September 28, 2021 | education

| Given:

ABC – right triangle;

Angle C = 90 degrees;

tg b = √21 / 2;

Find cos b.

Solution:

tg b = sin b / cos b = √21 / 2;

Hence we obtain that sin b = √21 and cos b = √2.

Hence, cos b = √2.

Answer: cos b = √2.

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