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Circles, sectors and arcs - EduqasArea of a circle

Circles are 2D shapes with one side and no corners. The circumference is always the same distance from the centre - the radius. Sectors, segments, arcs and chords are different parts of a circle.

Part of MathsGeometry and measure

Area of a circle

The formula to calculate the area of a circle, with radius \(r\) is: \(\text{area of a circle} = \pi r^2\)

Example

Calculate the area of the clock face. Give your answer to one decimal place.

Clock face with radius, 8cm

\(\text{Area} = \pi \times 8^2\)

Remember to use . The radius must be squared first before multiplying by \(\pi\).

The exact value for the area is = \(64\pi\). Rounded to 1 decimal place, the area is 201.1 cm2.