we know that
The area of fabric is 20 square feet
so
Verify each option
a) a square with a side length of 4 feet
the area of a square is
A=b^2
we have b=4 ft
substitute
A=4^2=16 ft^2
16 ft^2 < 20 ft^2 ------> is ok
b) a rectangle with a length of 4 feet and a width of 3.5 feet
the area of rectangle is
A=LW
substitute
A=4(3.5)=14 ft^2
14 ft^2 < 20 ft^2 --------> is ok
c) a circle with a radius of about 2.5 feet
The area of a circle is
A=pir^2
A=(3.14)(2.5)^2=19.63 ft^2
19.63 ft^2 < 20 ft^2 ------> is ok
therefore
the answer is option C
