Question 385272
The cost of a pizza varies directly with the square of its radius. If the cost of the pizza is $8.00 when the radius is 8 inches, find the cost when the radius increases to 10 inches.
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Cost c proportional to r^2
{{{c(alpha)r^2}}}
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{{{c=kr^2}}} where k is  the constant of proportionality
r=8 c =8
plug these values
{{{8=k*8^2}}}
divide both sides by 8^2
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k=8/8^2
k=1/8
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k=1/8 r=10
c=kr^2
c=1/8*10^2
c=100/8
c=$ 12.50
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m.ananth@hotmail.ca