# Square, Tangent, and Two Congruent & Tangent Circles

- Author:
- Tim Brzezinski

Creation of this applet was inspired by a problem posted on Twitter by Antonio Gutierrez .
, where

**Feel free to change the size of the circles by moving point***A*or*B*.**Goal:**Prove that**How can you formally prove what this applet informally illustrates?***r*= the radius of either circle.## New Resources

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