Question

A rectangle has one of its diagonals equal to 5 cm. If the breadth of the rectangle is 3 cm, then its area is

• A. $12c{m}^2$
• B. $18c{m}^2$
• C. $20c{m}^2$

Answer 1

The correct option is A $12c{m}^2$


Using pythagoras theorem,
$CD=\sqrt{(AC{)}^2-(DA{)}^2}$
$CD=\sqrt{25-9}=\sqrt{16}=4cm$

Area of rectangle ABCD = length × breadth
$\Rightarrow \text{Area}=4\times 3=12c{m}^2$