Question

how many square feet of dry - wall are needed for the wall shown in the figure to the right? for the given wall, 253 square feet of dry - wall is needed.

Explanation:

Step1: Calculate area of large rectangle

The large rectangle has length $l = 19$ feet and width $w = 15$ feet. The area of a rectangle is $A = l\times w$. So, $A_{1}=19\times15 = 285$ square - feet.

Step2: Calculate area of small rectangle

The small rectangle has length $l = 8$ feet and width $w = 4$ feet. The area of a rectangle is $A = l\times w$. So, $A_{2}=8\times4 = 32$ square - feet.

Step3: Calculate area of the wall

The area of the wall (the area of dry - wall needed) is the area of the large rectangle minus the area of the small rectangle. $A = A_{1}-A_{2}=285 - 32=253$ square - feet.

Answer:

253 square feet