A toothed wheel of diameter 50 cm is attached to a smaller wheel of diameter 30 cm. How many revolutions will the smaller wheel make when the larger one makes 30 revolutions?

If the ratio of the areas of two circles is 25 : 4, then the ratio of their diameters is :

1. 5 : 2

2. 25 : 4

3. 625 : 16

4. 16 : 625

If the length of a side of a square is same as length of the diameter of a circle, then the ratio of their areas is :

1. 1 : π

2. 2 : π

3. 4 : π

4. 8 : π