Perimeter and Area — Answer Key
Part A: Fix the Sentence
Each sentence has an error. Rewrite it correctly on the line.
1. Fix the sentence:
A rectangle with sides 7 cm and 2 cm has a perimeter of 14 cm.
Corrected: A rectangle with sides 7 cm and 2 cm has a perimeter of 18 cm.
The corrected sentence is: "A rectangle with sides 7 cm and 2 cm has a perimeter of 18 cm." The error was wrong sum: the original sentence "A rectangle with sides 7 cm and 2 cm has a perimeter of 14 cm." needed to be fixed.
2. Fix the sentence:
A rectangle that is 6 units long and 3 units wide has an area of 9 square units.
Corrected: A rectangle that is 6 units long and 3 units wide has an area of 18 square units.
The corrected sentence is: "A rectangle that is 6 units long and 3 units wide has an area of 18 square units." The error was wrong product: the original sentence "A rectangle that is 6 units long and 3 units wide has an area of 9 square units." needed to be fixed.
3. Fix the sentence:
Area is the distance around the outside of a shape.
Corrected: Area is the space inside a shape.
The corrected sentence is: "Area is the space inside a shape." The error was wrong definition: the original sentence "Area is the distance around the outside of a shape." needed to be fixed.
Part B: Fill in the Blank
Write the missing word or number on each line.
1. A rectangle is 9 cm long and 3 cm wide. Its perimeter is 24 cm.
Perimeter means adding all four sides: 9 + 3 + 9 + 3 = 24 cm.
2. A square with sides of 6 cm has an area of 36 square cm.
Area of a square is side times side, so 6 x 6 = 36 square cm.
3. To find the area of a rectangle, you multiply the length by the width.
The area formula for a rectangle is length x width, so you need to know the length to multiply it by the width.
4. A rectangle is 4 m long and 7 m wide. Its area is 28 square m.
Area = length x width, so 4 x 7 = 28 square m.
Part C: True or False?
Read each statement. Circle True or False.
1. A square with 3 cm sides has a perimeter of 12 cm.
True False
True. A square has 4 equal sides, so 4 x 3 = 12 cm.
2. A rectangle that is 5 cm by 4 cm has an area of 9 square cm.
True False
False. The area is 5 x 4 = 20 square cm, not 9 square cm.
3. Area is measured in square units.
True False
True. Area counts how many squares fit inside a shape, so it uses square units like square cm or square m.