Geometry | Unit 3 | Lesson 8: Are They All Similar? | Practice Problems

This is an invalid proof that all isosceles triangles are similar. Explain which step is invalid and why.

Which statement provides a valid justification for why all circles are similar?

• All circles have the same shape—a circle—so they must be similar.

• All circles have no angles and no sides, so they must be similar.

• I can translate any circle exactly onto another, so they must be similar.

• I can translate the center of any circle to the center of another, and then dilate from that center by an appropriate scale factor, so they must be similar.

Which pair of polygons is similar?

• 
• B

• C

• D

Determine if each statement must be true, could possibly be true, or definitely can't be true. Explain or show your reasoning. Two equilateral triangles are similar.

An equilateral triangle and a square are similar.