Counting triangles in a figure

1. The figure is a triangle with 5 lines from the top vertex to the base.
2. By size (in units of the smallest triangle's area): 6 of size 1, 5 of size 2, 4 of size 3, 3 of size 4, 2 of size 5, 1 of size 6.
3. Total: 21 triangles.

Answer: 21

1. The figure is a triangle with 1 line from the bottom-left vertex and 2 lines from the bottom-right vertex to the opposite sides.
2. By size (in units of the smallest triangle's area): 1 of size 1, 1 of size 1.2, 1 of size 1.8, 2 of size 3, 1 of size 3.2, 3 of size 4, 1 of size 4.8, 2 of size 6, 2 of size 8, 1 of size 12.
3. Total: 15 triangles.

Answer: 15

1. The figure is a square with both diagonals and the square formed by joining the midpoints of its sides.
2. By size (in units of the smallest triangle's area): 8 of size 1, 4 of size 2, 4 of size 4, 4 of size 8.
3. Total: 20 triangles.

Answer: 20