Question

What is formulae for circumference when given radius or diameter

Answer 1

The formula for circumference is C=2$\pi$r, where r is the radius. If given the diameter, divide by 2 to get the radius.

Answer 2

The formula of the circumference is πd(pi multiply by the diameter) or 2πr(pi multiply by 2 times the radius[which is the same as the diameter])


The formula for the area of a circle is
$\pi r ^{2}$