Circle Measurements Worksheet

Name:

Date:

📚 Part 1: WALT, Success Criteria & Quick Checks

WALT: Calculate the diameter and radius of a circle from a given circumference.

Success criteria: I can define radius and diameter; I can use C = πd to find d = C ÷ π; I can find r by halving the diameter.

1. Which statements about circumference are correct? (Tick all that apply)

C = πd

C = πr²

C = 2πr

d = 2r

2. Given a circumference of 31.4 cm, use π ≈ 3.14. What is the diameter (to one decimal place)?

5.0 cm

10.0 cm

2.5 cm

3. If C = 10π cm, which is the correct diameter?

5π cm

10 cm

20π cm

4. Which step shows how to find the radius from a given circumference?

r = C × π

r = (C ÷ π) ÷ 2

r = C ÷ 2

✏️ Part 2: Short Answer Practice

5. A bicycle wheel has circumference 188.5 cm. Find the diameter and radius. Show your working. (Use π ≈ 3.14)

6. A circular garden has circumference 25 m. Calculate the diameter and radius. Give answers in metres to two decimal places. Show your working.

7. A jar lid measures 15π cm around. Write the diameter and radius in terms of π.

8. Challenge / Extension: Explain in one or two sentences why π is used in the formula for circumference (you may draw or use a string around a circle to help).

Differentiation & dyslexia-friendly options: Use manipulatives (discs, string) or work orally if writing is hard. Key steps: 1) d = C ÷ π, 2) r = d ÷ 2. Highlight each step in a different colour if helpful.