The length of a side and a diagonal of a rhombus are 5cm and 8cm respectively. Find the area of the rhombus?

The length of a side =5cm and 

Diagonal of a rhombus = 8cm 

As, we know that,

The halves of diagonals and a side of a rhombus from a right angled triangle with side as hypotenuse.

Let the length of the other diagonal =2x.

⇒x²+(8/2)²= 5²

⇒x²+16=25

⇒x²=25-16

⇒x²=9

⇒x=3

The measure of the another diagonal of the rhombus = 2×3 = 6 cm

∴Area of the rhombus = ×Diagonal of a rhombus×Measure of the another diagonal 

⇒Area of the rhombus = ×8×6=24 cm²