Question

Ernesto built a wooden car for a soap box derby. He is painting the top of the car blue and the sides black. He already has enough black paint, but needs to buy blue paint. He needs to know the approximate area of the top of the car to determine the size of the container of blue paint he should 1 buy. He measured the length to be 9 feet 11 - inches, and the width to be inch less than 3 feet. 2 What is the surface area of the top of the car? What is the most accurate area measurement Ernesto can use to buy his paint?

Answer 1

The surface area of the top of Ernesto's car is approximately 29.46 square feet, calculated by first converting all measurements to inches, then multiplying the length and width, and converting the result back to square feet.

Step-by-step explanation:

To calculate the surface area of the top of the car, we first need to use consistent units. Since the length is given in feet and inches, let's convert the width to the same units. The width is given as half an inch less than 3 feet, which is 35.5 inches because 3 feet is equivalent to 36 inches (3 feet × 12 inches/foot). Now, the measurement of the length is 9 feet 11.5 inches. We convert this to inches as well by multiplying the feet by 12 and adding the inches, so this gives us 119.5 inches (9 feet × 12 inches/foot + 11.5 inches). To find the surface area (SA) in square inches, we multiply the length by the width:

SA = length × width

SA = 119.5 inches × 35.5 inches

SA = 4242.25 square inches

To find the area in square feet, we divide the number of square inches by the conversion factor, since there are 144 square inches in a square foot:

SA = 4242.25 square inches ÷ 144 square inches/square foot

SA ≈ 29.46 square feet

So, Ernesto will need to know the surface area of the top of his car is approximately 29.46 square feet to buy the correct amount of blue paint.