CAIE IGCSE Mathematics C5.3.1 Carry out calculations involving the circumference & area of a circle.

Practise calculating circumference and area of circles and semicircles, including reverse problems, unit changes and exact forms.

Exam points

use radius or diameter to calculate circle area, circumference or semicircle perimeter
work backwards from a given area or circumference to find radius or diameter
convert final circle measurements between cm and mm when the answer unit changes

[Maximum number: 2]

The diagram shows a circle, centre O, radius 11 cm. C, F, G and H are points on the circumference of the circle.
The line AD touches the circle at C and is parallel to the line EG. B is a point on AD and angle $A B O=140^{\circ}$ .

Find, in terms of $\pi$ , the circumference of the circle.

___ cm

$22\pi$ final answer
M1 for $2\times11\times\pi$ .

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C5.3.1 Carry out calculations involving the circumference and area of a circle. question 1