# GED Math Extra Prep: Perimeter and Area of Rectangles

If the GED Math test gives you a question involving the perimeter or area of a rectangle, you’ll save time if you memorize those formulas beforehand. The following practice questions will let you know if you need to refresh your memory.

## Practice Questions

*Both questions are based on the following rectangle.*

- What is the area of the rectangle? (Give your answer to the nearest square inch.)

**A.**10

**B.**17

**C.**18

**D.**210 - If the rectangle were enlarged by a factor of 3 (so that its sides became 3 times as long as they were previously), what would be the ratio of the new perimeter to the old perimeter?

**A.**1:3

**B.**1:9

**C.**3:1

**D.**9:1

## Answers and Explanations

- The correct answer is D.
The width of the rectangle is given as 7 inches. Note that the length of the rectangle is 2.5 feet, which needs to be multiplied by 12 to convert into inches:

*l*= 2.5 (12) = 30Multiply the length by the width to calculate the area of the rectangle:

*A*=*lw*= (30)(7) = 210Hence, Choice (D) is the correct answer.

- The correct answer is C.
The perimeter

*P*of a rectangle of length*l*and width*w*is given by the following formula:*P*= 2*l*+ 2*w*The new length of the rectangle is 3

*l*and the new width is 3*w,*so the new perimeter will simply be 3 times longer than the old perimeter:Hence, the ratio of the new perimeter to the old perimeter is 3:1, making Choice (C) correct.