Room A has an area of 99 square feet. Room B is 405 square feet. Both rooms are square. Each wall will be the square root of
. The numbers 99 and 405 are non-perfect squares. So √99 and √405 cannot be integers. For example, √99 = 9. 94987. The three dots show that the number
. A number with a non-terminating decimal cannot be a rational number. We can estimate √99≈√100. The number 100

because √100=10. So each wall of Room A is about 10 feet long. Let's do the same steps for Room B. First, we estimate that √405≈√400. The number 400 is a perfect square. Why? Because

is 20. And 20 is an integer. Each wall of Room B is approximately 20 feet long. Both rooms are 10 feet high. Each room has four walls. So, the formula is (10×4+20×4)×10. Here are the solution steps: 10×4=40 and 20×4=80, then

=120 and

=1200 square feet. That's the total surface area he needs to paint.

Words You Can Use

rational number

inequality

integer

repeating decimal

repetend

terminating decimal

non-terminating

variable

inverse relationship

constant

coefficient

squared

square root

perfect square

non-perfect square

cubed

cube root

cubic unit

radical

radicand

inverse operation