<PRE><B>Question 182628</B>
How many angles are formed by 12 distinct rays with a common endpoint? 
Do you add up all the possible combinations? Or do you just have the twelve angles? 
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Each pair of rays form an angle.
The number of pairs is 12C2 = (12*11)/(1*2) = 66 angles

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Cheers,
Stan H.
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