Circle Measurements Worksheet

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📚 Part 1: Core calculations

Formulas: Circumference = 2πr or πd. Area = πr². Use π = 3.14 unless told otherwise. Include units; show working.

1. Circle A — radius = 7 cm.

Show working:

Final answers:

Circumference = ________ cm · Area = ________ cm²

2. Circle B — diameter = 16 cm.

Show working:

Final answers:

Circumference = ________ cm · Area = ________ cm²

3. Circle C — radius = 0.5 m. (Convert units where helpful.)

Show working:

Final answers:

Circumference = ________ m · Area = ________ m²

4. Circle D — diameter = 22 cm. Use π = 22/7 for an exact fractional approach, then give a decimal to 2 d.p.

Show working (fraction and decimal):

Final answers:

Circumference = ________ cm · Area = ________ cm²

5. Circle E — radius = 12 cm. Find circumference and area; then calculate the perimeter of a semicircle of the same radius (curved edge + diameter).

Show working:

Final answers:

Circumference = ________ cm · Area = ________ cm² · Semicircle perimeter = ________ cm

✏️ Part 2: Applied problems

6. A circular garden has diameter 8 m. A path 0.5 m wide runs all around the garden (externally). Find the area of the path. Show working and give your answer to 2 d.p.

Area of path = ________ m²

7. A round cake has radius 9 cm. The baker needs to wrap the edge with ribbon — enough to go once around the cake and an extra 10 cm for tying. How long of ribbon should the baker cut? Include units.

Ribbon length = ________ cm

8. A circular water tank has circumference 31.4 m. Find its radius and area (use π = 3.14). Show working and include units.

Radius = ________ m · Area = ________ m²