Concept 2 of 2

Counting shapes inside a figure

To count triangles in a complex figure: count one-piece triangles first, then 2-piece (made of two adjoining small ones), then 3-piece, etc.

Example

A triangle divided into 4 small triangles (with the middle one inverted) has 4 small + 1 big = 5 triangles total.

💡 Tip:Be systematic — going by size class avoids missing or double-counting.