The hypotenuse of a right-angled triangle is 25 cm. One of its legs is 15. Find the other leg.

In order to find the length of the second leg in a right-angled triangle, if the length of the hypotenuse is known from the condition and the length of the hypotenuse is 25 cm and one of the legs is 15 cm, we will recall and apply the Pythagorean theorem.

Let’s remember the Pythagorean theorem.

The square of the hypotenuse is equal to the sum of the squares of the legs.

a ^ 2 + b ^ 2 = c ^ 2;

Let’s plug the known values into the Pythagorean theorem and solve the resulting equation:

15 ^ 2 + b ^ 2 = 25 ^ 2;

225 + b ^ 2 = 625;

b ^ 2 = 625 – 225;

b ^ 2 = 400;

b = 20 cm length of the second leg.

Answer: 20 cm length of the second leg.