In a right-angled triangle ABC, the hypotenuse AB = 5 sin A = 0.4 what is the BC leg?

To solve this problem, we use the definition of sine. The sine of an angle in a right-angled triangle is the ratio of the opposite leg to the hypotenuse. In our task, just given: the hypotenuse and sine of the angle, and you need to find the opposite leg. Using the formula, we will solve our problem:

sin A = BC / AB;

From here we find BC:

BC = sin A * AB = 0.4 * 5 = 2 (cm)

Answer: BC = 2 cm.