Enlarging circles
A circle with radius of one centimetre can be enlarged by drawing a new circle with a radius two, three, ten or any number times the size of the original.
On the left is a circle with radius one centimetre and diameter two centimetres. On the right is a circle with radius three centimetres and diameter six centimetres.
It is beyond the expectations of year 5 to calculate the circumference or area of circles, but we can see by overlaying the smaller circle a number of times on top of the larger one, that the area of the larger circle is a great deal more than three times the smaller one.
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