Geometry
Watch this video to learn about the parts of a circle
Remember:
\(Radius = \frac{1}{2}diameter\)
\(Diameter = 2 \times radius\)
Circumference of a circle
For any circle with a diameter, d, the circumference, C, is found by using the A simple piece of arithmetic you type into a spreadsheet to perform a calculation. The plural of 'formula' is 'formulae'.:
\(C = \pi d\)
where \(\pi = 3.14\)
Question
Calculate the circumference of the circle shown below.
\(C = \pi d\)
\(= 3.14 \times 20\)
\(= 62.8cm\)
Question
Calculate the circumference of the circle shown below.
As you can see from the diagram, the radius is 12 cm.
Remember \(Diameter = 2 \times radius\)
\(Diameter = 2 \times 12 = 24cm\)
\(C = \pi d\)
\(= 3.14 \times 24\)
\(= 75.36cm\)