Question

The area of a circular field is 154 m2. Find the time taken by an athlate to complete
2 rounds if she is jogging at the rate of 5 km/hr.

Answer 1

22/*r*r=154
   r*r=49
  r=7
therefore, perimeter=2*22/7*7=44
the distance traveled by her=2*44=88=.088km
we know that- speed =distance/time;
5=.088/t
 then, t=0.88/5=0.176.hr.

Answer 2

area of circle = [tex] \pi r^2 [/tex]
              154 = [tex] \frac{22}{7} * r^2 [/tex]
              $\sqrt{49}$ = r
            r = 7 m
circumference = $2 \pi r$
                      = $2 * 2 * \frac{22}{7} * 7$
                       = 88m
time = ditance / speed
        = $\frac{88}{5000} hr.$
        = $\frac{11}{625} h$