Area & Perimeter questions for Primary 6 Maths

Every answer with the reasoning behind it. Worth reading after you have tried the set — or on its own, if you are a parent marking it.

1. A circle has a radius of 7 cm. What is its circumference? (Take π = 22/7)

   Answer: 44 cm

   Circumference = 2 × 22/7 × 7 = 44 cm.

2. A circle has a radius of 7 cm. What is its area? (Take π = 22/7)

   Answer: 154 cm²

   Area = 22/7 × 7 × 7 = 154 cm².

3. A circle has a diameter of 28 cm. What is its radius?

   Answer: 14 cm

   The radius is half the diameter: 28 ÷ 2 = 14 cm.

4. A semicircle has a radius of 14 cm. What is its area? (Take π = 22/7)

   Answer: 308 cm²

   Whole circle: 22/7 × 14 × 14 = 616 cm². Half of that is 308 cm².

5. A quadrant has a radius of 21 cm. What is its area? (Take π = 22/7)

   Answer: 346.5 cm²

   Whole circle: 22/7 × 21 × 21 = 1386 cm². A quarter of that is 346.5 cm².

6. A figure is a rectangle 24 cm by 15 cm with a triangle of base 24 cm and height 10 cm removed from it. What is the remaining area?

   Answer: 240 cm²

   Rectangle 24 × 15 = 360 cm², triangle 24 × 10 ÷ 2 = 120 cm², and 360 − 120 = 240 cm².

7. What is the perimeter of a semicircle with radius 7 cm? (Take π = 22/7)

   Answer: 36 cm

   Curved part: 22/7 × 7 = 22 cm. Plus the diameter 14 cm gives 36 cm.

8. A circle of radius 10 cm is cut from a square of side 20 cm. What area of the square is left? (Take π = 3.14)

   Answer: 86 cm²

   Square: 20 × 20 = 400 cm². Circle: 3.14 × 10 × 10 = 314 cm². 400 − 314 = 86 cm².

9. A square has an area of 49 cm². What is its perimeter?

   Answer: 28 cm

   7 × 7 = 49, so each side is 7 cm and the perimeter is 4 × 7 = 28 cm.

10. A rectangular lawn is 18 m by 12 m. Turf costs $8 per square metre. What is the cost of turfing the whole lawn?

    Answer: $1728

    The lawn is 18 × 12 = 216 m², and 216 × $8 = $1728.