What radius of a circle is required to inscribe a square with an apothem of 4.95 inches?a. 5inb. 6inc. 7ind. 8inPlease explain how to get the answer, I want to know how to do this and not just be given the answer

we know that
The apothem goes from the center to mid-point in one of the square sides.
then
If the apothem is -------> 4.95 in
so
the length of one side of the square is 2 * 4.95--------> 9.9 in
the diameter of the circle is equals to the diagonal of the square

applying the Pythagorean theorem

a²+ b²= c² 
a = b ---------> 9.9 in

2a² = c² 
c²=2 * 9.9²  
c²=196.02----------> c=√196.02---------- > c=14 in
the diameter is 14 in
so 
the radius r=14/2----------> r=7 in

the answer is the option 
c. 7 in