Question 552723
I don't see your diagram but assuming that the sides of the square enclosure will be tangent to (just touching) the circumference of the circular pen, then the diameter of the circle will be exactly equal to the length of the side of the square.
So you will need to find the diameter (D) of the circular pen whose circumference (C) is given as 35 feet.
{{{C = pi*D}}} or 
{{{D = C/pi}}} Use {{{pi = 3.14}}} as an approximation.
{{{D = 11.1465}}}
So the length of one side of the square would be 11.1465 feet.
The amount of fencing needed would be equal to the perimeter of the square or four times the length of one side.
{{{4*11.1465 = 44.586}}}feet.
Since you did not include a list of possible estimates, you can choose the correct answer yourself.