On the screen, we see two triangles ABC and A1B1C1 in blue color.
Length of sides, angles and area of these two triangles are written. We know that two triangles are similar if their three angles are same, even if lengths of their sides are different. We can freely move the four points A, B, A1 and B1 . Let us observe how the area of these triangles changes when we move these four points and change the angles of these similar triangles using their corresponding slide bars.

Question to think about.
1. What relation do we see between the sides and area of the triangles?
2. Find the ratio of the area of these two triangles and compare it with the ratio of squares of the corresponding sides. What do we observe?