Intermediate · 9. Coordinate area, dissection and curved regions
Choose convenient coordinates, use complements (subtract the unwanted pieces) or determinants, and check how each point divides its segment; combine perimeter and area conditions when needed.
AMC Australia · Intermediate · Selected Topics
Recognise the clues and choose a suitable method.
Explain each step in the five examples.
Solve real competition problems and spot the mistakes you need to fix.