help me please , i don’t understand what this means !

Answer:
[tex]B.\ \pi =\frac{C}{2r}[/tex]
Step-by-step explanation:
[tex]We\ are\ given\ that,\\C=2\pi r\\Hence,\\We\ now\ need\ to\ recreate\ this\ equation\ in\ terms\ of\ \pi,\\Hence,\\C=2\pi r\\\pi r =\frac{C}{2} [Transposing\ 2\ to\ the\ RHS]\\\pi =\frac{C}{2r}[Transposing\ r\ to\ the\ RHS]\\Hence,\\[/tex]
[tex]\pi =\frac{C}{2r}[/tex]