Area is 63 sq. Inches. The length is 9 ft. What is width

Question

The are of a box top is 63 sq. In. The length of box is 9 ft. What is the width?

Answer 1

Remember that area = length times width, A = lw.  This is a formula to memorize, you will be using it often.

 

So let's plug in the given information, making sure the units work out.  Checking the units is an important step in ANY problem:

 

Area, A = 63 sq inches (sq inches means inches squared, or inches x inches).  

length, l = 9 feet.

 

Uh oh.  If the area is in square inches, I need BOTH my length and width in inches.  So I need to convert that length.  (Alternatively I could convert the area to square feet, it is your choice.  It is a rule and something you should always check for:  the units on one side of the equation MUST equal the units on the other side of the equation.) 

 

So, if 12 inches = 1 foot (a conversion you should memorize -- think of a school ruler so you can visualize this), how many inches is 9 feet?

 

12 inches / 1 ft = x inches/ 9 ft

(write those fractions up and down instead of slanted sideways and you will see you can cross multiply to solve for x)

 

Now that you have the number of inches of the length, put that in the area formula:

 

Area = length times width, A = lw

 

Divide both sides by the length to get the answer for the width.  Your answer will be in inches. 

 

 

If you need the answer in feet, you can set up a proportion again:

 

(12 inches / 1 ft) = ( width in inches / width in ft)

 

Good luck!

 

 

Answer 2

PROBLEM

 

Area is 63 sq. Inches. The length is 9 ft. What is width
The are of a box top is 63 sq. In. The length of box is 9 ft. What is the width?

 

SOLUTION

 

AREA = LENGTH • WIDTH, A = l·w

 

1 foot = 12 inches, so length

 

l = 9 ft · (12 in / 1 ft) = 118 in

 

A = 63 in² = l·w = 118 · w

 

w = 63 / 118 ≈ 0.5338983051 in