Answer:
800 cm²
Step-by-step explanation:
Look at the picture.
We have three rectangles. The formula of an area of a rectangle:
[tex]A=lw[/tex]
l - length
w - width
Rectangle I:
[tex]A_I=7\cdot20=140\ cm^2[/tex]
Rectangle II:
[tex]A_{II}=6\cdot20=120\ cm^2[/tex]
Rectangle III:
[tex]A_{III}=18\cdot30=540\ cm^2[/tex]
The area of number 4:
[tex]A=A_{I}+A_{II}+A_{III}[/tex]
Substitute:
[tex]A=140+120+540=800\ cm^2[/tex]
