Answer: Bonnie must purchase 25 square feet of cloth.
Explanation:
In order to waste the least amount of material, the length of each side of the square piece of cloth must be equal to the diameter of the circular banner that she wants to cut out. The formula for determining the circumference of a circle is expressed as
Circumference = πd
Where
d represents the diameter of the circle
π is a constant whose value is 3.14
Since banner will have a circumference of 15.7 ft, then
3.14d = 15.7
d = 15.7/3.14
d = 5 ft
Area of the square cloth needed is
5² = 25 square feet