Question

How will the circumference of the circle change if it is dilated by a scale factor of 4?

16cm

The circumference will be 4 times greater than the original.
The circumference will be 16 times greater than the original.
The circumference will be 1/4 the original.
The circumference will be 1/16 the original.

Answer 1

C

Explanation:

Just took the test

Answer 2

The circumference of a circle has the formula:

C = 2 π r

Now when it is dilated by a factor of 4, this only means that the radius is also multiplied by a factor of 4, therefore the new circumference is:

C’ = 2 π (4 r)

C’ = 8 π r

So it also grows 4 times.

Answer:

The circumference will be 4 times greater than the original.