question_answer

The areas of two concentric circles are \[962.5\text{ }c{{m}^{2}}\]and \[1386\text{ }c{{m}^{2}}\]respectively. The width of the ring is _____.

A)  \[3.4\text{ }cm\]                    

B)  \[3.5\text{ }cm\]                    

C)  \[3.2\text{ }cm\]         

D)         \[3.1\text{ }cm\]