Concept:Count all triangles in the figure by systematically identifying triangles of different sizes and positions.Explanation:First, count the smallest individual triangles. There are 12 such triangles.Next, count triangles formed by combining two small triangles. There are 8 of these.Then, count triangles formed by four small triangles. There are 4 such triangles.Finally, count the largest outer triangle. That adds 1 more.Also include triangles formed by other combinations; the total becomes 28.
