In triangle ABC, angle C is straight, sine A = 0.2, BC = 5. Find AB.

In a right-angled triangle, the sine of an angle is the ratio of the leg opposite to this angle to the hypotenuse of the triangle. In the triangle ABC opposite the angle A lies the leg BC, and the hypotenuse is AB. Then: sinA = BC / AB; 5 / AB = 0.2; 5 / AB = 2/10; 5 / AB = 1/5; AB = 5 * 5 (the main properties of the proportion “cross to cross”); AB = 25 conventional units.
Answer: AB = 25 conventional units.