Skip to content

Library Solve Practice

Search 7,000+ topics/

Color theme

Library Solve Practice

Search everything About Expii Contributors

Library
Math
Geometry
Circles in Geometry
Circle Concepts
Similarity of Circles

Practice problem

Similarity of Circles

By EElise Molinaro

Which of the following equations represents the scale factor needed to either decrease or increase the size of a circle?

Choose one answer

Option A: A

$x=\frac{r_1}{r_2}$

Option B: B

$x=\frac{r_2}{r_1}$

Option C: C

$r_1=\frac{x}{r_2}$

Option D: D

$r_2=\frac{x}{r_1}$

Report a problem

What needs fixing?

Read explanations Rated practice

For a more Thought Full world.

Learn

Library
Search
Solve
Practice

Expii

About Expii
Contributors
Blog archive
Contact
Conduct

Family

LIVE
Po-Shen Loh

Free explanations from a community of curious people.© 2026 Expii, Inc.Terms Privacy

Find a topic

Type a concept, like “slope” or “photosynthesis”.

↑ ↓ to choose · Enter to openSearch explanations and problems