There is a rectangular tank of length 180 m and breadth 120 m in a circular field. If the area of the lad portion of the field is `40000 m^(2)`, what is the radius of the field ? (Take `pi = (22)/(7)`)

Options

A. 130 m/मी०
B. 135 m/मी०
C. 140 m/मी०
D. 145 m/मी०

Answer

C

Explanation

टैंक सहित वृताकार मैदान का क्षेत्रफल = आयाताकर टैंक का क्षेत्रफल + भूभाग का क्षेत्रफल
`= 180 xx 120 + 40000`
` = 21600 + 40000`
`= 61600` वर्ग मी.
अब,
`pi r^(2) = 61 600`
`rArr r^2 = (61 600 xx 7)/( 22)`
`therefore r = sqrt( 19600) = 140` मी.