The sides of the rectangle are 8cm and 15cm. Find the diagonal of this rectangle.

In order to find the length of the diagonal of a rectangle, if we know the lengths of the sides of the rectangle 8 cm and 15 cm, we will consider a right-angled triangle formed by the sides of the rectangle and its diagonal.

The diagonal of the rectangle in this triangle will be the hypotenuse of the right triangle.

Let’s remember and apply the Pythagorean theorem:

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

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

We apply the formula and get:

c = √ (a ^ 2 + b ^ 2) = √ (8 ^ 2 + 15 ^ 2) = √ (64 + 225) = √289 = 17 cm diagonal length of the rectangle.