Suppose x is any positive number. circle 1: center (5, 4) and radius 5x circle 2: center (5, 4) and radius 2x why is circle 1 similar to circle 2? circle 1 and circle 2 have the same radius. circle 1 is a dilation of circle 2 with a scale factor of 2.5. circle 1 is a dilation of circle 2 with a scale factor of 0.4. circle 1 is congruent to circle 2.