The circumference of a circle is $100 \pi \mathrm{cm}$. What is the radius of the circle?
(A) $20 \mathrm{~cm}$
(B) $100 \mathrm{~cm}$
(C) $50 \mathrm{~cm}$
(D) $25 \mathrm{~cm}$
(E) $10 \mathrm{~cm}$

Part B: Each correct answer is worth 6.
The circumference of a circle with radius $r$ is equal to $2 \pi r$.

When $2 \pi r=100 \pi, r=\frac{100 \pi}{2 \pi}=50 \mathrm{~cm}$.

ANSWER: $(\mathrm{C})$