The amount of metal he will need to cover the back of the shelves is 180 inches².
The figure above is like a composite figure. Therefore, lets find the area.
Area of the composite figure
The area of the figure is the sum of the whole individual 2 dimensional shapes in the composite figure.
Therefore, two rectangles can be drawn from it.
area of rectangle = lw
where
l = length
w = width
Therefore,
area of rectangle 1 = 9 × 8 = 72 inches²
area of rectangle 2 = 6 × 18 = 108 inches²
Total area = 108 + 72 = 180 inches²
Therefore, the amount of metal he will need to cover the back of the shelves is 180 inches².
learn more on area here: https://brainly.com/question/25849553
