Draw a triangle ∆A1B1C1 on a card-sheet and cut it out. Measure ∠A1, ∠B1, ∠C1. Draw two more triangles AA2B2C2 and AA3B3C3 such that ∠A1 = ∠A2 = ∠A3, ∠B1 = ∠B2 = ∠B3, ∠C1 = ∠c2 = ∠c3 and B1C1 > B2C2 > B3C3. Now cut these two triangles also. Measure the lengths of the three triangles. Arrange the triangles in two ways as shown in the figure.Check the ratios A1B1/A2B2, B1C1/B2C2. You will notice that the ratios are equal. Similarly, see whether the ratios A1C1/A3C3, B1C1/B3C3, A1B1/A3B3 are equal. What do you observe?

Draw a triangle ∆A1B1C1 on a card-sheet and cut it out. Measure ∠A

1.	Draw a triangle ∆A1B1C1 on a card-sheet and cut it out. Measure ∠A1, ∠B1, ∠C1. Draw two more triangles AA2B2C2 and AA3B3C3 such that ∠A1 = ∠A2 = ∠A3, ∠B1 = ∠B2 = ∠B3, ∠C1 = ∠c2 = ∠c3 and B1C1 > B2C2 > B3C3. Now cut these two triangles also. Measure the lengths of the three triangles. Arrange the triangles in two ways as shown in the figure.Check the ratios A1B1/A2B2, B1C1/B2C2. You will notice that the ratios are equal. Similarly, see whether the ratios A1C1/A3C3, B1C1/B3C3, A1B1/A3B3 are equal. What do you observe?
Answer» From the activity we observe that, when corresponding angles of two triangles are equal, the ratios of their corresponding sides are also equal i.e., their corresponding sides are in the same proportion.