Question

You are redecorating your room and the only thing left to paint is your door. You’re only going to paint the side that faces the inside of your room. The door is 6 feet 8 inches tall and 30 inches wide. You need to know the surface area of the side of the door to determine how much paint to buy. The hardware store sells paint by how much covers a square foot. What is the surface area you should report to the hardware store? (Hint: First find the number of square inches in 1 square foot.)

Answer 1

Answer: Then the surface area that you should report to the hardware store is 15 ft^2.

Explanation:

Remember that the area of a rectangle of length L and width W is

A = L*W

In this case, we can think in the door as a rectangle, where:

L = 6ft + 8in

W = 30in

Now, we know that in the hardware store they sell paint by how much covers a square foot, then we must calculate the area of the door in square feet.

Then the first step would be to replace all the units by ft.

We know that:

1ft = 12in.

Then we have that:

(1ft/12in) = 1

Then we have that:

8in = 8in*1 = (8in/12in)*1ft = 0.6... ft

(the 3 dots means that the 6 repeats infinitely)

And;

30in = 30in*1 = 30in*(1ft/12in) = 2.5ft

Then the measures of the door are:

L = 6ft + 0.6...ft = 6.6...ft

W = 2.5ft

The area will be:

A = L*W = 6.6...ft*2.5ft = 15 ft^2

Then the surface area that you should report to the hardware store is 15 ft^2.