In triangle ABC, angle C is straight, AC = 6, cos A = 0.6. Find AB.

Given:
right-angled triangle ABC;
angle C = 90;
cos A = 0.6;
AC = 6;
Find: the length of the hypotenuse AB -?
Decision:
Consider a right-angled triangle ABC.
The cosine of the angle in a right-angled triangle is equal to the ratio of the adjacent leg to the hypotenuse. Hence:
cos A = AC / AB;
AB = CA / cos A;
AB = 6: 0.6;
AB = 60 * 6;
AB = 10 – the length of the hypotenuse of the right-angled triangle ABC.
Answer: AB = 10.