Question

Find the area of the unfolded envelope shown. (Measures are given in inches)

• A. 72

Answer 1

The correct option is A 72

$\text{Area of triangle}=\frac{1}{2}\times Base\times Height$

$\text{Area of triangle}1=\text{Area of triangle}3$
$=\frac{1}{2}\times 7\times 4=14inc{h}^2$
$\text{Area of triangle}2=\text{Area of triangle}4$
$=\frac{1}{2}\times 4\times 4=8inc{h}^2$
$\text{Area of rectangle}=Length\times Breadth$
$\text{Area of rectangle}=7\times 4=28inc{h}^2$
$\text{Area of envelope}=\text{Area of triangle}1+\text{Area of triangle}3+\text{Area of triangle}2+\text{Area of triangle}4+\text{Area of rectangle}$
$Areaofenvelop=(14+14+8+8+28)inc{h}^2=72inc{h}^2$