In a right-angled triangle ABC (angle C = 90 °), the hypotenuse AB = 8 cm, sin of angle A = 0, 4. Find the boat length BC.

In the problem, the hypotenuse and sine of the angle opposite to the BC leg are given, we find BC through the sine of the angle A.

The sine of angle A is the ratio of the opposite leg to the hypotenuse:

Sin A = BC: AB.

From the resulting equation, we find the BC:

BC = AB × sin A.

By the condition of the problem, it is known that AB = 8 cm, sin A = 0.4, we substitute the values into the equation and solve it:

BC = 8 × 0.4;

BC = 3.2 cm.