# How to find the length of a diagonal of a rectangle with length given as l and breadth given as b.

We will use the properties of the rectangle in order to find the length of the diagonal.

### Answer: d (diagonal) = **√** (l^{2} + b^{2})

Let us see how we will use the properties of the rectangle in order to find the length of the diagonal.

**Explanation**:

Let us consider a rectangle ABCD with AB as length a, BC as breadth b, and AC as diagonal d as shown in the figure below.

We have been given a rectangle with length as a and breadth as b.

We also know that all angles of the rectangle are 90°. Hence, the angle ABC = 90°.

ABC also forms a right-angled triangle AB = a as perpendicular and BC = b as the base and AC = d as the hypotenuse.

Hence, diagonal can be calculated using the Pythagoras theorem.