Area = pi * r^2
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A pizza with a 7-inch diameter has a radius of 3.5 inches.
Area = pi*3.5^2 = 38.48 sq. in.
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A pizza with a 14-inch diameter has a radius of 7 inches.
Area = pi*7^2 = 153.93 sq. in.
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The smaller pizza costs $5 = 500 cents, so it costs 500/38.48 = about 13 cents per sq. in.
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It costs $12 = 1200 cents, so it costs 12/153.93 = about 8 cents per sq in.
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The larger pizza is a better buy in terms of the cost per sq. in.
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Done, hope that helped
