Circumference and area of a circle: Class 7 practice
Circumference C = 2πr = πd and area A = πr². Read the method, follow the three worked examples, then try the six questions.
What you should know first
- Squares
- Multiplying fractions
The idea behind circumference and area of a circle
Circumference C = 2πr = πd and area A = πr². Use π = 22/7 when the radius is a multiple of 7, otherwise 3.14 unless told.
Step-by-step method
- Find the radius (half the diameter).
- C = 2πr; A = πr².
- Give units: cm for C, cm² for A.
Worked example 1 (Basic)
Find the circumference of a circle of radius 14 cm (π = 22/7).
- C = 2 × 22/7 × 14 = 88 cm
- Answer: 88 cm
Worked example 2 (Standard)
Find the area of a circle of diameter 28 cm (π = 22/7).
- r = 14 cm
- A = 22/7 × 14² = 616 cm²
- Answer: 616 cm²
Worked example 3 (Challenge)
A circle has circumference 220 cm. Find its area (π = 22/7).
- r = 220 ÷ (2 × 22/7) = 35 cm
- A = 22/7 × 35² = 3850 cm²
- Answer: 3850 cm²
Common mistakes and misconceptions
- Using diameter in πr²
- Writing area in cm
Practice questions
- (Basic) Find the circumference of a circle of radius 7 cm (π = 22/7).
- (Basic) Find the circumference of a circle of radius 42 cm (π = 22/7).
- (Standard) Find the area of a circle of diameter 84 cm (π = 22/7).
- (Standard) Find the area of a circle of diameter 56 cm (π = 22/7).
- (Challenge) A circle has circumference 88 cm. Find its area (π = 22/7).
- (Challenge) A circle has circumference 176 cm. Find its area (π = 22/7).
Answer key with full working
- Q1: C = 2 × 22/7 × 7 = 44 cm → Answer: 44 cm
- Q2: C = 2 × 22/7 × 42 = 264 cm → Answer: 264 cm
- Q3: r = 42 cm → A = 22/7 × 42² = 5544 cm² → Answer: 5544 cm²
- Q4: r = 28 cm → A = 22/7 × 28² = 2464 cm² → Answer: 2464 cm²
- Q5: r = 88 ÷ (2 × 22/7) = 14 cm → A = 22/7 × 14² = 616 cm² → Answer: 616 cm²
- Q6: r = 176 ÷ (2 × 22/7) = 28 cm → A = 22/7 × 28² = 2464 cm² → Answer: 2464 cm²
Syllabus note
This skill is listed under "Perimeter and Area" for Class 7 in the NCERT/CBSE books. ICSE, IGCSE, IB and state boards may teach it in a different chapter or year.
Answers on this page are generated and automatically re-checked by a second, independent calculation. They have not been reviewed by a teacher — if you spot a problem, tell us on WhatsApp.
Related practice and notes
Frequently asked questions
Which chapter is circumference and area of a circle in?
"Perimeter and Area", Class 7 Maths (NCERT/CBSE). Other boards may place it differently.
How were the answers checked?
Answers on this page are generated and automatically re-checked by a second, independent calculation. They have not been reviewed by a teacher — if you spot a problem, tell us on WhatsApp.