Ruiz needs to buy a countertop for a kitchen. He calculated the area to be 16 square feet. The actual area is 15.4 square feet. What is Ruiz's percentage error?

(How do you solve this?)

First, subtract the two values:

16 - 15.4 = 0.6

Now divide this to the actual area:

0.6 / 15.4 = 0.038961039

Multiply by 100:

0.038961039 * 100 = 3.8961039

So the percent error is approximately 3.9%