In triangle ABC, angle C is 90, AC = 4, cosine of angle A is 0.5 Find AB

By the definition of trigonometric functions, the cosine of an angle in a right-angled triangle is equal to the ratio of the adjacent leg AC to the hypotenuse AB. We write down the ratio:

cos A = AC / AB;

Let’s find what the leg AB will be equal to:

AB = AC / cos A.

Substituting the numerical values from the condition of the problem, we get:

AB = 4 / 0.5 = 8;

Answer: leg AB = 8.