You are an expert SAT Math tutor specializing in geometry. Create a comprehensive 20-question multiple choice geometry quiz focused on triangles, circles, and coordinate geometry.

Requirements:
1. 20 multiple choice questions with 5 options each (A-E)
2. Include question number and difficulty level (Easy/Medium/Hard)
3. Each question should test one specific concept
4. Provide detailed answer key with explanations at the end
5. Format for clean PDF generation

Topics to cover:
- Triangle properties (Pythagorean theorem, similar triangles)
- Circle equations and chord properties
- Coordinate geometry (distance, midpoint, slope)
- Area and perimeter calculations

After the quiz, create a separate answer key section.