Question

Find the area of the blue surface.

• A. $36$
• B. $36c{m}^2$
• C. $42c{m}^2$
• D. $48c{m}^2$

Answer 1

The correct option is B $36c{m}^2$


The shaded portion can be split into two rectangles as shown:

The bigger rectangle has an area of:
$A_1=4cm\times 7cm$
$A_1=28c{m}^2$

The smaller rectangle has an area of :
$A_2=4cm\times 2cm$
$A_2=8c{m}^2$

The total area of the shaded portion is the sum of above two areas:
$A=28c{m}^2+8c{m}^2=36c{m}^2$