in how much time will he return at starting point

Area of square field = 60025 m

Thus, side = √60025 = 245 m.

Perimeter = 245 * 4 = 980 meters

Speed = 18 kmph = 5m/s

Time = Distance / speed

= 980 / 5

= 196.

Thus, it will take 196 seconds for the man to return at the starting point.

\( Area=60025\ m^2\ \ \ and\ \ \ Area=a^2\\\\\ \ \ \Rightarrow\ \ \ a^2=60025\ m^2 \ \ \Rightarrow\ \ \ a=245\ m\\\\\ \Rightarrow\ \ \ the\ perimeter\ of\ a\ square:\\\\.\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ P=4a=4\cdot245\ m=980\ m=0.98\ km\\\\ Speed=18 \frac{km}{h} \ \ \ and\ \ \ Speed= \frac{P}{time} \\\\18= \frac{0.98}{time}\\\\\ \ \ \Rightarrow \ \ \ time= \frac{0.98}{18}\\ hr=\frac{0.98}{18} \cdot3660\ s=196\ s=3\ min\ 16\ s\\ \)

\( Ans. \ he\ will\ return \ after\ 3\ minutes\ 16\ seconds. \)