Question

What is the area of number 4?

Answer 1

800 cm²

Explanation:

Look at the picture.

We have three rectangles. The formula of an area of a rectangle:

`A=lw`

l - length

w - width

Rectangle I:

`A_I=7\cdot20=140\ cm^2`

Rectangle II:

`A_(II)=6\cdot20=120\ cm^2`

Rectangle III:

`A_(III)=18\cdot30=540\ cm^2`

The area of number 4:

`A=A_(I)+A_(II)+A_(III)`

Substitute:

`A=140+120+540=800\ cm^2`