question_answer

A cow is tied to a pole, fixed to the midpoint of a side of a square field of dimensions 40 m x 40 m, by means of 14 m long rope. Find the area that the cow can graze.   

A)  \[254\,{{m}^{2}}\]             

B)  \[308\,{{m}^{2}}\] 

C)         \[245\,{{m}^{2}}\]        

D)         \[380\,{{m}^{2}}\]             

Correct Answer: B

Solution :

        The area that cow can graze is in the form of semicircle.             Radius of semicircle   Length of rope\[=14m\]     Required area \[=\frac{1}{2}\times \pi {{r}^{2}}\] \[=\frac{1}{2}\times \frac{22}{7}\times 14\times 14=308\,{{m}^{2}}\]