Question

there is a circle pond and footpath runs along its boundary.a man walks around it, exactly once.keeping close to the edge.if his step is 545 cm long and he takes exactly 400 step to go around the pond . what is the diameter of the pond?

Answer 1

perimeter of circular pond = 600 * 44cm 
= 26400 cm
= 264 m

now,
perimeter of circular pond = 264m = 26400 cm
2πr = 264m = 26400 cm
πr = 132m = 13200 cm 
r = 132/3.14m = 13200/3.14 cm
r = 42 m = 4200 cm (approx)

Answer 2

Each step = 545 cm
400 steps = 400 * 545 = 218000 cm
Circumference of pond = 218000 cm
C = 2 * π * r
218000 = 2 * 22/7 * r
218000 * 7/22 = 2 * r
69363.63 = d                [2 * r = d]
∴ Diameter of pond = 69363.637 cm