Question

Which of the following expressions can be used to find the area of the polygon? Select all that apply.

An irregular shape that is a rectangle with a piece missing from the upper right corner. The bottom length is twenty feet. The left side width is nine feet. The top length is eighteen feet with a rectangle cut out of the upper right corner. The right side width is six feet.
A. (9 × 20) – 6
B. (9 × 18) – (6 × 2)
C. (9 × 18) + (6 × 2)
D. (20 × 6) + (18 × 3)
E. (20 × 9) – (3 × 2)

Answer 1

Option E

The shape is got using the expression: (20 X 9) - (3 X 2)

Explanation:

to get the area of the shape, all we need to do is subtract the area of the smaller rectangular cut out from the area of the bigger rectangle.

The main trick here will be identifying the dimensions of both the larger rectangle and the smaller rectangle.

Dimensions of the larger rectangle:

Since we are told that the cut out is at the upper right corner, we can get the dimensions of the larger rectangle using the bottom length and the left width.

Thus we have Length = 20 feet, width = 9 feet

Dimensions of the smaller rectangular cutout.

We can get this by subtracting the dimensions of the top and right edges of the shape from their counterparts in the larger rectangle ( length an width)

length of cutout = ( 20-18) = 2 feet

width of cutout = (9-6) = 3 feet

Hence, the area of the shape is got using the expression:

(20 X 9) - (3 X 2)