Roofing Shingles Are Sold by the "Square

Multiple Choice

Roofing shingles are sold by the "square". A square can cover an area of roof that is 13 ft long and 13 ft wide. A home improvement store sells shingles by the square or by the bundle. The area of a roof is
Find the minimum number of squares needed to shingle this roof. Round up to the nearest square.

A) 20
B) 19
C) 21
D) 18