One of the legs of a right-angled triangle is 12 cm, and the hypotenuse is 13 cm.

One of the legs of a right-angled triangle is 12 cm, and the hypotenuse is 13 cm. Find the second leg and the hypotenuse of the triangle.

Consider a triangle ABC, with an angle C = 90 °.

Let’s find the unknown leg according to the Pythagorean theorem (in a right-angled triangle, the square of the hypotenuse is equal to the sum of the squares of the legs), i.e. a ^ 2 + b ^ 2 = c ^ 2.

13 ^ 2 = 12 ^ 2 + b ^ 2;

b ^ 2 = 169 – 144 = 25;

b = √ 25 = 5.

Answer: 5 (cm)