Question

The table shows the side length and approximate area of an octagonal stop sign.

Area of a Stop Sign

A 2-column table with 5 rows. The first column is labeled side length (inches), x with entries 5, 10, 15, 20, 25. The second column is labeled area, f(x) with entries 120; 480; 1,080; 1,920; 3,000.

Which function can be used to compute the approximate area, in square inches, of a stop sign if it has a side length of x inches?

f(x) = 4.8x2
f(x) = 4x2
f(x) = (4.8)x
f(x) = (4)x

Answer 1

f(x) = 4.8x^2

Reason: f/x^2 = 120/25 = 4.8, and 4.8·x^2 gives 4.8·25 = 120, 4.8·100 = 480, etc., matching the table.