Centre, radius, diameter, circumference — and the formulas C = πd and A = πr²
Change the radius with − and +, then watch the diameter, circumference and area update. (π = 3.14)
Radius r
Diameter d = 2r
8
units
Circumference C = πd
25.12
units
Area A = πr²
50.24
sq units
Using π = 3.14