Let's begin by setting up a proportion which we can use to solve for the number of square miles occupied by a family of 4 (4 people):
7,200,000,000 : 65,755 = 4 : x
Now let's set the cross products of the proportion equal to each other and solve the equation for x:
(7,200,000,000)(x) = (65,755)(4)
7,200,000,000x = 263,020
x = 263,020 / 7,200,000,000
x = 0.00003653055 square miles
So we now know that 4 people will occupy 0.00003653055 square miles.
Now we need to convert square miles to square feet as per the answer required in our problem:
1. √0.00003653055 = 0.00604405125 mi
2. (0.00604405125 mi)(5,280 / mi) = 32 feet
3. (32)2 = 1024 square feet
Look like choice D is an excellent approximation of our answer.
This problem required a two-prong approach: first set up a proportion to find the space in square miles occupied by 4 people and then convert that space to square feet.
Thanks for submitting this problem and glad to help.
God bless, Jordan.