How many triangles are there in the following figure?

- A6
- B10
- C11
- D12
Solution & Step-by-step Explanation
Let us label the vertices of the main triangle as at the top, at the bottom-left, and at the bottom-right. The line from the top vertex meets the base at point . Lines drawn from the vertex intersect the line segment and side .
Counting the triangles systematically by combining smaller regions:
* Triangles consisting of 1 single region: 5 triangles
* Triangles consisting of 2 combined regions: 4 triangles
* Triangles consisting of 3 combined regions: 2 triangles
* The largest main triangle (): 1 triangle
Adding these together:
Therefore, the total number of triangles in the figure is 12.
Counting the triangles systematically by combining smaller regions:
* Triangles consisting of 1 single region: 5 triangles
* Triangles consisting of 2 combined regions: 4 triangles
* Triangles consisting of 3 combined regions: 2 triangles
* The largest main triangle (): 1 triangle
Adding these together:
Therefore, the total number of triangles in the figure is 12.