Question

Which of the following is not equivalent to the formula for the circumference of a circle, C = 2 pir ?

Answer 1

i think one of them is obvious since the rest used direct division

Answer 2

try a guess

Answer 3

um c ?

Answer 4

C/2r = pi came from c = 2pi r by dividing both sides by 2r

Answer 5

wait wha?

Answer 6

@abb50

Answer 7

\[C = 2\pi r\]
that's your original equation

if you divide both sides by 2r
\[\frac C{2r} = \frac{\cancel 2 \pi \cancel r}{\cancel{2r}}\]

Answer 8

so... ?
c ; the one that equals pie

Answer 9

@abb50