Grade 3 Perimeter and Area Worksheet for 8-Year-Olds | 20 Objective & 10 Subjective Questions

Instructions

Hi there, Math Explorer! Today, we are learning about Perimeter.

The perimeter is the total distance around the outside of a shape. Imagine you are a little ant walking all the way around the edge of a field. The total distance you walk is the perimeter!

To find the perimeter, you simply add the lengths of all the sides together.

For example, for a triangle with sides 3 cm, 4 cm, and 5 cm, the perimeter is 3 + 4 + 5 = 12 cm. Good luck!

Part A: Objective Questions

Read each question carefully and write your answer in the space provided or choose the correct option.

1. A square has sides that are 4 cm long. What is its perimeter? ________ cm
2. A rectangle has a long side of 8 m and a short side of 3 m. What is its perimeter? ________ m
3. A triangle has sides of 6 cm, 8 cm, and 10 cm. What is its perimeter? ________ cm
4. A shape has five sides. The lengths are 2 cm, 4 cm, 3 cm, 4 cm, and 5 cm. What is its perimeter? ________ cm
5. A perfect triangle with three equal sides of 5 inches each. What is its perimeter? ________ inches
6. What is the perimeter of a rectangle with sides 10 cm and 5 cm?
   a) 15 cm     b) 25 cm     c) 30 cm
7. A square has one side that is 7 meters long. What is its perimeter?
   a) 7 m     b) 14 m     c) 28 m
8. The word "perimeter" means to...
   a) Measure the space inside a shape.
   b) Add up the lengths of all the sides.
   c) Multiply the length and width.
9. A stop sign has 8 equal sides. If one side is 10 cm long, what is the perimeter?
   a) 18 cm     b) 80 cm     c) 10 cm
10. Which calculation finds the perimeter of a triangle with sides 4, 5, and 6?
    a) 4 + 5 + 6     b) 4 x 5 x 6     c) 6 - 5 - 4
11. A rectangle has a length of 9 cm and a width of 6 cm. Its perimeter is ________ cm.
12. A shape has six equal sides. Each side is 3 meters long. The perimeter is ________ m.
13. A square's perimeter is 20 cm. How long is one of its sides? ________ cm.
14. A triangle has a perimeter of 18 inches. All its sides are equal. How long is one side? ________ inches.
15. A rectangle has a perimeter of 14 m. Its width is 2 m. What is its length? ________ m.
16. True or False: To find the perimeter of a square, you can multiply the length of one side by 4. ________
17. True or False: Perimeter is the space inside a shape. ________
18. True or False: A rectangle with sides 5m and 4m has a perimeter of 18m. ________
19. True or False: A shape with longer sides will always have a larger perimeter than a shape with shorter sides. ________
20. True or False: You find the perimeter of a rectangle by just adding its length and width. ________

Part B: Subjective Questions

For these questions, show your work by writing down the addition number sentence and your final answer.

1. A rectangle has sides of 15 cm and 10 cm. What is its perimeter?
   Work:
   
   Answer:
2. A triangle has sides that are 9 m, 12 m, and 5 m long. Find the perimeter.
   Work:
   
   Answer:
3. Find the perimeter of a shape with five sides measuring: 6 cm, 7 cm, 8 cm, 9 cm, and 10 cm.
   Work:
   
   Answer:
4. Mia wants to put a fence around her square garden. One side of the garden is 5 meters long. How much fencing does she need in total?
   Work:
   
   Answer:
5. A rectangular swimming pool is 25 meters long and 10 meters wide. If you walk all the way around the edge of the pool, how far have you walked?
   Work:
   
   Answer:
6. The perimeter of a triangle is 30 cm. Two of the sides are 10 cm and 12 cm long. How long is the third side?
   Work:
   
   Answer:
7. A rectangular park has a total perimeter of 120 meters. Its length is 40 meters. What is its width?
   Work:
   
   Answer:
8. Draw a square that has a perimeter of 24 cm. Label the length of each side.
   
   
   
   
   
9. Draw a rectangle that is not a square but has a perimeter of 18 cm. Label the lengths of the sides.
   
   
   
   
   
10. A farmer's field has six sides. The side lengths are 20 m, 30 m, 15 m, 25 m, 35 m, and 10 m. What is the perimeter of the field?
    Work:
    
    Answer:

Answer Key

Part A: Objective Questions

1. 16 cm (4+4+4+4)
2. 22 m (8+3+8+3)
3. 24 cm (6+8+10)
4. 18 cm (2+4+3+4+5)
5. 15 inches (5+5+5)
6. c) 30 cm
7. c) 28 m
8. b) Add up the lengths of all the sides.
9. b) 80 cm
10. a) 4 + 5 + 6
11. 30 cm (9+6+9+6)
12. 18 m (3x6)
13. 5 cm (20 ÷ 4)
14. 6 inches (18 ÷ 3)
15. 5 m (14 - 2 - 2 = 10; 10 ÷ 2 = 5)
16. True
17. False (That is area.)
18. True (5+4+5+4 = 18)
19. True
20. False (You must add all four sides, not just two.)

Part B: Subjective Questions

1. Work: 15 + 10 + 15 + 10 = 50 cm
   Answer: 50 cm
2. Work: 9 + 12 + 5 = 26 m
   Answer: 26 m
3. Work: 6 + 7 + 8 + 9 + 10 = 40 cm
   Answer: 40 cm
4. Work: 5 + 5 + 5 + 5 = 20 m
   Answer: 20 m
5. Work: 25 + 10 + 25 + 10 = 70 m
   Answer: 70 m
6. Work: 10 + 12 = 22; 30 - 22 = 8 cm
   Answer: 8 cm
7. Work: 40 + 40 = 80; 120 - 80 = 40; 40 ÷ 2 = 20 m
   Answer: 20 m
8. The student should draw a square with all four sides labeled as 6 cm. (6+6+6+6 = 24 cm)
9. The student should draw a rectangle with sides labeled to add up to 18. Examples: Length=8, Width=1; Length=7, Width=2; Length=6, Width=3; Length=5, Width=4.
10. Work: 20 + 30 + 15 + 25 + 35 + 10 = 135 m
    Answer: 135 m