Perimeter, Area, and Surface Area — Answer Key
Part A: Fix the Sentence
Each sentence has an error. Rewrite it correctly on the line.
1. Fix the sentence:
The area of a square with side 6 cm is 24 cm squared.
Corrected: The area of a square with side 6 cm is 36 cm squared.
Area equals s squared, so 6 times 6 equals 36 square centimeters, not 24.
2. Fix the sentence:
The perimeter of a pentagon with sides 4, 5, 6, 7, 8 cm is 28 cm.
Corrected: The perimeter of a pentagon with sides 4, 5, 6, 7, 8 cm is 30 cm.
Adding 4 plus 5 plus 6 plus 7 plus 8 gives 30 centimeters total around the pentagon.
3. Fix the sentence:
A book cover that is 2 ft by 2 ft has area 4 ft.
Corrected: A book cover that is 2 ft by 2 ft has area 4 square feet.
Area measures surface coverage, so the unit must be square feet, written as ft squared.
Part B: Fill in the Blank
Write the missing word or number on each line.
1. The area of a square with side 9 inches is 81 square inches.
Nine times nine equals 81, so the area is 81 square inches.
2. A picture frame has sides 5 cm, 7 cm, 5 cm, and 7 cm; its perimeter is 24 cm.
5 plus 7 plus 5 plus 7 equals 24 centimeters around the frame.
3. A square tile measures 1 ft on each side, which equals 12 inches per side.
One foot is exactly twelve inches, so each side measures 12 inches.
4. A square garden has side 11 m; its perimeter is 44 meters.
Perimeter equals 4 times s, and 4 times 11 equals 44 meters.
Part C: Short Answer
Answer each question in one or two complete sentences.
1. Mia has a square scarf with side length 8 inches. What is its area in square inches?
Sample answer: Area equals 8 times 8, which is 64 square inches.
Eight squared is 64, so the scarf covers 64 square inches of surface.
2. A hexagonal stop sign has six equal sides of 12 cm. What is the perimeter?
Sample answer: Perimeter equals 6 times 12, which is 72 centimeters.
Six equal sides of 12 cm each give a total perimeter of 72 centimeters.