Question

a well of diameter 150cm has a stone parapet around it .If the length of the outer edge of the parapet is 660cm,then find the width of parapet<br />

Answer 1

perimeter of circle =2×22/7×r
660cm=2×22/7×r
here,r=75+x
2×22/7×75+x=660cm
75+x=660×1/2×7/22
75+x=105
x=105-75
x=30