In triangle ABC, angle C is 90 °, BC = 1, sinA = 0.2 find AB.

Three points of the plane that do not lie on one straight line, connected by line segments, are a triangle.

If one of the angles of a triangle is 90º, then this triangle is right-angled. The side that is opposite the right angle is called the hypotenuse, and the other two sides are called the legs.

Since, according to the condition of the problem, the length of the opposite leg BC and the sine of angle A are known, to calculate the length of the hypotenuse AB, we apply the theorem of sines. The sine of an acute angle of a right triangle is the ratio of the opposite leg to the hypotenuse:

sin A = BC / AB;

AB = BC / sin A;

AB = 1 / 0.2 = 5 cm.

Answer: the length of the hypotenuse AB is 5 cm.