Chapter 11.6, Problem 31PPS

To determine

To calculate : area of wall to be painted

Answer to Problem 31PPS

84 square feet

Explanation of Solution

Given information : The base of wall is 12 feet wide and the top is 8 feet wide. The wall is 9 feet high. Dimensions of rectangular window are 2 feet and 3 feet.

Formula used : Area of trapezoid $=\frac{1}{2}$ (sum of parallel sides) (height)

Calculation :

Sides are equal to 12 feet and 8 feet

Sum of parallel sides = 12 + 8 = 20 feets

Height = 9 feets

Now find area of trapezoid

Area of trapezoid $=\frac{1}{2}$ $\times$ (sum of parallel sides) $\times$ (height) $=\frac{1}{2}\times (12+8)\times (9)=90$ square feets

Also, dimensions of rectangular window are 2 feet and 3 feet.

Now find area of the rectangular window

Area of the rectangular window $=$ length $\times$ breadth $=2\times 3=6$ square feets

So,

Area to be painted = Area of the rectangular window - Area of trapezoid

  $=90-6$

  $=84$ square feets