Practice!

Sample Problem

What is the area of the envelope (including the stamp area) ?

The area of the envelope is in.2.

Solution

Solution:

Area of rectangle = base × height

 = 16 in. × 9 in.

 = 144 in.2.

 =

 

 = 40 in.2

Area of the envelope = Area of rectangle + Area of triangle ABE

 = 144 in.2 + 40 in.2

The area of the envelope is 184 in.2