P6 Circles and curved boundaries
semicircle area — radius 21 cm
A semicircle has radius 21 cm. Find its area. Use π = .
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The pattern behind it: Circles and curved boundaries
Find the space inside a circle shape or the distance around its boundary.
In this one. Area measures the surface inside a shape. Use square centimetres, and take the appropriate fraction of the whole circle area.
How to spot it
'Area' asks for square centimetres from the radius. 'Circumference' or 'perimeter' on a curved edge asks for plain centimetres from the diameter instead.
Common mistake
Children give a circumference answer in square units, or find a circle's area without squaring the radius first, mixing up the two kinds of measurement.
Try one like it
Standard circle area — radius 14 cm A circle has radius 14 cm. Find its area. Use π = 22/7.The 33 problem patterns
All 33 patterns, one to a page — the 19 behind Primary 5 and 6 word problems, and the skills the younger years are built on. The bar model, how to spot it in the question, and the mistake children make. A booklet you can print. Free.
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