In a right-angled triangle, the legs are 3 cm and 4 cm. Find the hypotenuse.

In order to find the hypotenuse in a right-angled triangle, you need to use the Pythagorean theorem, which says that the square of the hypotenuse is equal to the sum of the squares of the legs. Since we know the length of the legs, we need to square the length of each leg and add:

3 ^ 2 + 4 ^ 2 = 3 * 3 + 4 * 4 = 9 + 16 = 25

The square of the hypotenuse is 60, to find the hypotenuse, you need to derive the root of 25:

√25 = 5.

Answer: hypotenuse = 5 cm.