SOLUTION: If a small circle's diameter is a large circle's radius, then the small circle is ____% of the large circle's area? a) 20 b) 25 c) 30 d) 40 e) 50

Question 288049: If a small circle's diameter is a large circle's radius, then the small
circle is ____% of the large circle's area?
a) 20 b) 25 c) 30 d) 40 e) 50
Answer by Edwin McCravy(20055) (Show Source): You can put this solution on YOUR website!




The green line is the small circle's diameter and also the 
large circle's radius.  Suppose the green line is 2 inches long.
Then the small circle's radius is 1, the red line:



Area of small circle = 

Area of large circle = 

Since the big circle's area is 4 times the small circle's area,
the small circle's area is  of the big circle's area
and  is the same as 25%. So the correct choice is b)

Edwin

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