Stage 9 - Q1 - 2 marks
Find the circumference; give 2 d.p.
Hint
Choose the correct circle formula and identify the radius.
Stage 9 - Q2 - 2 marks
Find the area; give 2 d.p.
Hint
Choose the correct circle formula and identify the radius.
Stage 9 - Q3 - 2 marks
Find the circumference; leave your answer in terms of pi.
Hint
Choose the correct circle formula and identify the radius.
Stage 9 - Q4 - 2 marks
Find the area; leave your answer in terms of pi.
Hint
Choose the correct circle formula and identify the radius.
Stage 9 - Q5 - 2 marks
A circular mat has diameter \(15\) cm. Find its area to 2 d.p.
Hint
Halve the diameter before squaring.
Stage 9 - Q6 - 3 marks
Two circles have radii \(14\) cm and \(16\) cm. How much greater is the second area? Give an exact answer.
Hint
Subtract squared radii, not the radii themselves.
Stage 9 - Q7 - 3 marks
A pupil uses \(A=\pi\times30^2\) for a circle of diameter \(30\) cm. Correct the error.
Hint
Locate the diameter in the diagram mentally.
Stage 9 - Q8 - 4 marks
A circle has diameter \(34\) cm. Show an area formula using diameter, then apply it.
Hint
The factor of one half is squared.
Stage 9 - Q9 - 4 marks
A radius grows from \(19\) cm to \(20\) cm. Find the exact increases in circumference and area.
Hint
A one-centimetre radius increase has different effects on length and area.
Stage 9 - Q10 - 5 marks
Challenge: A wire of length \(32\pi\) cm forms one circle or two equal separate circles. Which option encloses more total area, and by how much?
Hint
Find the radius from the wire length separately for each option.