作者yoolooroo (YES!!)
看板GRE_Verbal
標題Re: [問題]一題來欣M2的數學
時間Sun Jun 24 20:34:15 2007
※ 引述《hjung (D~~~~~~!!)》之銘言：
: Rught triangle PQR is to be constructed in the xy-plane so that the right
: angle is at and PR is parallel to the x-axis.
: The x- and y-coordinates of P, Q, and R are to be integers that satisfy the
: inequalitues -4≦x≦5 and 6≦y≦16.
: How many different triangles with these properties could be constructed?
: (A) 100
: (B) 1,100
: (C) 9,900
: (D)10,000
: (E)12,100
: 答案是(C)
: 算了很久算不出來 請大家幫忙了~"~
: 謝謝^^
C11取2*C10取2*4=9900
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◆ From: 122.124.65.29
1F：推 hjung:謝謝^^ 140.114.194.2 06/24 22:16
2F：推 angeline107: 為何最後*4 ??? 61.64.136.86 06/25 09:24
3F：推 hjung:因為直角三角形可以上下左右翻轉 140.114.194.2 06/25 10:31