Why is circle 1 similar to circle 2? Circle 1: center (0, 9) and radius 14 Circle 2: center (0, 9) and radius 7

A. Circle 1 and circle 2 have the same center.
B. Circle 1 is a translation of circle 2.
C. Circle 1 is a dilation of circle 2 with a scale factor of 7.
D. Circle 1 is a dilation of circle 2 with a scale factor of 2.

1 Answer
Feb 27, 2018

See explanation.

Explanation:

The correct answer is #D#.

The two circles have the same center, but that is not required for the circles to be similar.

But the radii of the circles tell that circle #1# is is #2# times bigger than circle #2# (it has twice bigger radius). So the correct answer is

#D# - Circle 1 is the dillataion of #2# with the factor of #2#.