Question 1172018
If the radius of a circle is changed from 4dm to 8dm..
A. How is the circumference changed?
It's a function of the radius ---> it's doubled.
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B. How is the area changed?
It's a function of the square of the radius.
What do you think?
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C. What is the ratio of the perimeter?
To what?
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D. What is the ratio of the areas? 
Think about it.