Coordinate Geometry (Hard)
Late AMC 10/12 through early AIME — dense computation.
Coordinate Geometry: core idea
Right-angle conditions.
Example problem: hint and answer
Find the area of the triangle .
Hint: Translate the stated geometry into slopes, distances, or coordinates. Answer: 24.
Practice (9 problems — type your answers)
1. A circle through has center . Find .
2. The line through meets at . Find .
3. A square has adjacent vertices . Find its area.
4. Find the distance from to .
5. The perpendicular bisector of meets at . Find .
6. A line of slope through meets the -axis at . Find .
7. Find the area of .
8. Lines and meet at . Find .
9. A circle centered at is tangent to the -axis. Find area.