Question

Joe draws a circle with center (-2, 0) and a radius of 4 units. If the scale factor is 5/2, what is the radius of a similar circle with the same center?

Answer 1

The radius of a similar circle with center (-2, 0) has a length of 10 units.

Explanation:

The radius of the new circle (
`R`) is the product of the former radius (
`r`) and the scale factor (
`k`), that is to say:

`R = k\cdot r` (1)

If we know that
`k = (5)/(2)` and
`r = 4`, then the radius of the new circle is:

`R = k\cdot r`

`R = \left((5)/(2) \right)\cdot (4)`

`R = 10`

The radius of a similar circle with center (-2, 0) has a length of 10 units.