Question

15, explanation and answer

Answer 1

Answer:

10 gallons of paint

Step-by-step explanation:

First, find the surface area of the monument.

From inspection, this is made up of 4 congruent rectangles and 4 congruent triangles.

Area of a rectangle = width x length

Therefore, area of one rectangle of the monument:

13 x 40 = 520 ft²

Area of triangle = 1/2 x base x height

Therefore, area of one triangle of the monument:

1/2 x 13 x 11 = 71.5 ft²

Therefore, total surface area of the monument

= 4 x SA of rectangle + 4 x SA of triangle

= 4 x 520 + 4 x 71.5

= 2080 + 286

= 2366 ft²

We are told that one gallon of paint can cover 239 ft², and that paint can only be bought by the gallon.

Divide the total surface area of the monument by the area one gallon of paint can cover to calculate how many cans of paint are needed.

2366 ÷ 239 = 9.89958159...

Therefore, 10 gallons of paint must be bought (since we need to round up as paint can only be bought by the gallon).