Find the length of the hypotenuse AB of a right-angled triangle ABC, if it is known that BC = 2.5 cm, angle B = 60 degrees.

As we know from the current course of the school curriculum in mathematics, the cosine of the angle is calculated as the ratio of the adjacent leg to the hypotenuse.
Judging by the condition of the task, the BC leg is adjacent to the angle, which is 60 °.
Let us determine with the help of how many centimeters it is possible to write down the length of the hypotenuse in our triangle, when from the condition of the task we know that the leg of the BC is 2.5 centimeters:
2.5: 1/2 = 2.5 * 2 = 5.
Answer: With such initial data, the length AB is 5 centimeters.