What is the area of the composite shape?

Hello !
First,the composite shape is composed by a rectangle and a portion of a semicircle.

You can express the area as the sum of the area of that rectangle and the area of the portion of the circle : 
A rectangle = L*I 
L=5 m
l = 2 m 

A rectangle = 5*2 = 10 m²

The missing semicircle (white) has the diameter 4 m.
So,the portion's area is the difference between the whole semicercle and that missing one.
Tho whole semicercle has the diameter 2+4+2 = 8 m = D

The area for the circle is π·R² or π·D²/4 ( because R = D/2 )

A = π·8²/4 = π·64/4 = 16π m²
Here we have a semicircle so we will divide the area by 2 :
16π m² / 2 = 8 π m²

The missing circle is part of a circle with the area A=π·D²/4=π·4²/4=4π m²

Here we have a missing semicircle so we will divide the area by 2 : 4/2 = 2m²

The area of the portion will be the difference : 8 - 2 = 6 m²

Thea area of the shape is 10+6 = 16 m²

If you don't understand,please tell me.Have a nice day !

She will need 5/8 bags for each square yard.