Rays, segments and diagonals
Name points with letters, rays and segments, draw a segment of a given length and count the diagonals of a polygon by solving a simpler problem.
- Germany: grade 5
- Iran: grade 3
Guide
We name points with letters: A, B and C. Segment AB has two ends. Ray AB starts at A, passes through B and goes on for ever.
A diagonal of a polygon is a segment joining two corners that are not next to each other.
When a problem is hard, solve it for a smaller polygon, spot the pattern, then come back to the real problem.