Question

A parallelogram has sides $30m$ and $14m$ and one of its diagonals is $40m$ long. Then, its area is:

• A. $168m^2$
• B. $336m^2$
• C. $372m^2$
• D. $480m^2$

Answer 1

The correct option is A $168m^2$

Area of parallalogram = $2\times areaoftriangle$

Area of triangle where three sides a,b,c are given is $\sqrt{s(s-a)(s-b)(s-c)}$, where $s=\frac{a+b+c}{2}$

Here $s=\frac{30+14+40}{2}=42$

$Areaof△=\sqrt{\left(42\right)\left(12\right)\left(28\right)\left(2\right)}=\sqrt{28224}=168m^2$

Therefore area of parallalogram = $336m^2$

Hence option B is correct