Planning & EstimatingQuestion 491 of 700
A roof has 1,800 square feet of surface. Adding 10 percent for waste, how many roofing squares should be ordered (1 square = 100 sq ft)?
a.18 squares
b.19 squares
c.20 squares
d.22 squares
Explanation
One roofing square covers 100 sq ft. Base area = 1,800 / 100 = 18 squares. Add 10 percent waste: 18 x 1.10 = 19.8 squares. Since material is sold in whole squares and you cannot under-order, round up to 20 squares. Option a ignores waste. Option b rounds 19.8 down, leaving a shortage. Always round material orders up.
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