Question

which expression represents the circumference of a circle when r is the radius and d is the diameter of the circle ?
`\: a. \: \pi \: d`
`b. \: \pi \: r`
`c. \: \pi \: d2`
`d. \: \pi \: r2`

Answer 1

which expression represents the circumference of a circle when r is the radius and d is the diameter of the circle ?

we know that

The circumference of a circle is equal to

`\begin{gathered} C=2\pi r \\ or \\ C=\pi d \end{gathered}`

where

r is the radius

d is the diameter

Remember that

d=2r -------> diameter is two times the radius