Question

Can someone please help me with this?

1. By what factor does the circumference change if the radius is tripled? Explain.

Answer 1

The circumference of a circle with radius $r$ is $2\pi r$. If the length of the radius is tripled, then the circumference becomes $2\pi(3r)=3\cdot2\pi r$, which is just 3 times the original circle's circumference.