The areas of two similar triangles are 81 cm² and 49 cm² respectively. If an altitude of the smaller triangle is 3.5 cm, then the corresponding altitude of the bigger triangle is

1. 9 cm

2. 7 cm

3. 6 cm

4. 4.5 cm

If ABC and BDE are two equilateral triangles such that D is mid-point of BC, then the ratio of the areas of triangles ABC and BDE is

1. 2 : 1

2. 1 : 2

3. 1 : 4

4. 4 : 1

If △ABC ~ △PQR, area of △ABC = 81 cm², area of △PQR = 144 cm² and QR = 6 cm, then length of BC is

1. 4 cm

2. 4.5 cm

3. 9 cm

4. 12 cm

In the adjoining figure, DE || CA and D is a point on BD such that BD : DC = 2 : 1. The ratio of area of △ABC to area of △BDE is

1. 4 : 1

2. 9 : 1

3. 9 : 4

4. 3 : 2