Question

Sierra applies a coat of epoxy paint to the four sides and floor of a rectangular swimming pool. The pool is 4 feet deep, 18 feet long, and 12 feet wide. One gallon of paint covers 155 square feet. Does sierra use 3 gallons of paint or 4 gallons of paint? Explain

Answer 1

Sierra needs 4 gallons of paint.

Step-by-step explanation:

To find out how many gallons of paint Sierra needs, we need to calculate the surface area of the swimming pool. The surface area can be found by adding up the areas of the four sides and the floor. The area of each side is 4 feet (depth) multiplied by 18 feet (length), which gives 72 square feet. The area of the floor is 18 feet (length) multiplied by 12 feet (width), which gives 216 square feet. The total surface area is 4 times the side area plus the floor area, which is (4 x 72) + 216 = 504 square feet.

One gallon of paint covers 155 square feet, so to find out how many gallons of paint Sierra needs, we divide the total surface area by 155. Therefore, Sierra needs 504 / 155 ≈ 3.25 gallons of paint. Since we cannot use a fraction of a gallon, Sierra will need to purchase 4 gallons of paint to have enough for the job.

Answer 2

4 gallons of paint

Step-by-step explanation:

We solve using the formula for surface area of rectangular prism.

A=2(wl+hl+hw)

Where:

w = Width

h = Height

l = Length

The pool is 4 feet deep, 18 feet long, and 12 feet wide.

Hence,

=2 × (12 × 18 + 4 × 18 + 4 ×12)

=672 square feet

One gallon of paint covers 155 square feet.

Hence,

155 square feet = 1 gallon of paint

672 square feet = x

Cross Multiply

155 square feet × x = 672 square feet × 1 gallon of paint

x = 672 square feet × 1 gallon of paint/ 155 square feet

x = 4.335483871 gallons of paint

Therefore, based on the calculation above, approximately to the nearest whole number, Sierra uses 4 gallons of paint