Maths Dictionary · JSS 1
Radius
Simple meaning
The distance from the centre of a circle to its edge. It is half the diameter.
Example
A circle with diameter 14 cm has radius 7 cm.
See it
From the Perimeter of Plane Shapes lesson. Try moving things around.
P = 2 × (5 + 3) = 16 cm
Walk round the edge: 16 one-centimetre steps. (Area would be 15 cm².) Drag the blue corner.
Length5 cm
Height3 cm