Primary 6 · Circle · Question type 6.2
Cut a circle into thin slices and arrange them as a rectangle one radius high to see why the area rule works.
Try the question yourself, or watch the lesson first.
Primary 6, on the MOE Primary Mathematics syllabus.
The lesson · 2 minutes 30 seconds
Watch: the area of a circle with a radius of 10 cm
Another worked example
The floor inside an observatory dome is a circle of area 1384.74 m². Find the diameter of the floor. (Take π = 3.14.)
The working · Five lines
Written out in full, the way it should appear on paper.
The answer is 42 m.
Practise · Modelled on top school exam questions
Try it yourself first. Open the solution when you want to see the steps. No sign-up is needed. These questions are written by Mathweave, not copied from school papers.
Try it yourself
Halve the diameter before finding the area of the badge.
A round sewing badge has a diameter of 7 cm. Find the area of the badge. (Take π = 3.14.)
Ans: 38.465 cm²
The practice plan adds more questions and saved progress.
Next, include the straight edges of a semicircle or quarter circle in its perimeter. Perimeter of Semicircles and Quarter Circles →