Question

How do circumference and area change when the radius of a circle is doubled? Provide an example to support your answer.

Answer 1

@rational

Answer 2

@matt101

Answer 3

The equation for circumference is:
\[C=2 \pi r\]
Double the radius and you get:
\[C=2 \pi (2r)\]\[C=2 (2 \pi r)\]
What happened to the circumference?

Similarly, the equation for area is:
\[A= \pi r^2\]
Double the radius and you get:
\[A= \pi (2r)^2\]\[A= 4(\pi r^2)\]
What happened to the area?

Answer 4

They both doubled

Answer 5

@TheSmartOne

Answer 6

They did not double.