Re: [解題] 國三 圓

[Huawen (開心就好~)]

http://ppt.cc/wVt4
   __   __          __   __
設 OD = OA = r  且  AB = OC = 5
   __                    __
則 CD = √(r^2 - 5^2 ) = OE
   __   __
又 OE + OA = 10

則 √(r^2 - 5^2 ) + r = 10

   r = 25/4

圓面積 = (25/4)^2 * π

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