Basic Perimeter Calculations

📏 Measurement & Shapes (Grade 3)

Unit 6: Perimeter, Regularity, and Measurement Concepts

Interactive Practice for Elementary Geometry Formulas and Skills

🔢 Part 1: Perimeter Calculation (Units)

Formula Reminder: Perimeter is the distance around the outside of a shape (add all sides). Calculate the perimeter for the shapes described below.

Q1. Find the perimeter of a rectangle that is 12 cm long and 5 cm wide.

cm

Q2. What is the perimeter of a square sandbox with a side length of 8 meters?

m

Q3. A cereal box (cuboid) has a front face that is 7 inches tall and 4 inches wide. What is the perimeter of that face?

inches

Q4. A triangular field has sides measuring 5 m, 5 m, and 6 m. What is the total perimeter?

m

Q5. A regular pentagon (5 equal sides) has each side measuring 10 mm. What is its perimeter?

mm

Q6. Find the perimeter of a door which is 25 dm long and 15 dm wide.

dm

Q7. An irregular hexagon has sides: 3, 3, 3, 5, 5, and 5 units. Calculate the perimeter.

units

Q8. A stop sign (regular octagon) has 8 equal sides of 6 cm. What is the perimeter?

cm

Q9. The base of a triangular prism has sides that are all 4 inches long. What is the perimeter of the base?

inches

Q10. The base of a square-based pyramid has sides of 9 feet. What is the perimeter of its base?

feet

🎨 Part 2: Regular vs. Irregular Shapes

A Regular Shape has all sides and all angles equal. Is the following shape or description Regular (R) or Irregular (I)?

Q11. A square with all sides equal to 5 cm.

Regular Irregular

Q12. A rectangle with sides 8 cm and 4 cm.

Regular Irregular

Q13. A triangle with all three sides measuring 7 inches.

Regular Irregular

Q14. A pentagon whose sides are 5, 6, 7, 5, and 8 units long.

Regular Irregular

Q15. A hexagon with all sides equal, but some angles are sharp and others are blunt.

Regular Irregular

Q16. A shape where all four sides are equal, but the angles are not $90^{\circ}$.

Regular Irregular

Q17. A 5-sided shape with all sides and all interior angles being exactly the same.

Regular Irregular

Q18. A triangle with only two sides that are equal in length.

Regular Irregular

Q19. An 8-sided shape used as a stop sign, where all sides are the same length.

Regular Irregular

Q20. A quadrilateral (4-sided shape) where adjacent sides are equal, but opposite sides are not.

Regular Irregular

✅ Part 3: True or False Statements

Decide whether each statement about measurement and geometry is True or False.

Q21. The perimeter of a shape is measured in square units.

True False

Q22. A square is an example of a regular shape.

True False

Q23. To find the area of a rectangle, you multiply the length by the width.

True False

Q24. A cube has exactly 8 vertices (corners).

True False

Q25. All the faces of a cuboid must be squares.

True False

Q26. A centimeter (cm) is smaller than a meter (m).

True False

Q27. The area is the measurement of the boundary of a shape.

True False

Q28. A cone has two flat faces (circles) and one curved face.

True False

Q29. An irregular shape can have sides that are all different lengths.

True False

Q30. The side lengths of a $1 \text{ m} \times 1 \text{ m}$ square are the same as $100 \text{ cm} \times 100 \text{ cm}$.

True False

✍️ Part 4: Fill in the Blanks (Geometry Terms)

Complete the sentences using the correct measurement or geometry terms.

Q31. The formula for the Area of a rectangle is Length $\times$ __________.

Q32. A 3D shape with 6 square faces is called a __________.

Q33. A kilogram (kg) is equal to __________ grams (g).

Q34. The distance around the outside of any shape is its __________.

Q35. A rectangle has four right __________.

Q36. We use a ruler to measure the __________ of an object.

Q37. A triangular prism has a total of __________ faces.

Q38. The flat surfaces of a 3D shape are called __________.

Q39. $1 \text{ liter}$ (l) is equal to __________ milliliters (ml).

Q40. A shape that is not regular is called __________.

Answer Key

Q1. 34 cm

Q2. 32 m

Q3. 22 inches

Q4. 16 m

Q5. 50 mm

Q6. 80 dm

Q7. 24 units

Q8. 48 cm

Q9. 12 inches

Q10. 36 feet

Q11. Regular (R)

Q12. Irregular (I)

Q13. Regular (R)

Q14. Irregular (I)

Q15. Irregular (I)

Q16. Irregular (I)

Q17. Regular (R)

Q18. Irregular (I)

Q19. Regular (R)

Q20. Irregular (I)

Q21. False (F)

Q22. True (T)

Q23. True (T)

Q24. True (T)

Q25. False (F)

Q26. True (T)

Q27. False (F)

Q28. False (F)

Q29. True (T)

Q30. True (T)

Q31. Width

Q32. Cube

Q33. 1000

Q34. Perimeter

Q35. Angles

Q36. Length

Q37. 5

Q38. Faces

Q39. 1000

Q40. Irregular

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