Math CentralQuandaries & Queries


Question from Shon, a parent:

what is the formula for finding the number of angels that can be named by a given number of rays with the same endpoint?

Hi Shon.

Each angle is formed by combining two rays. If you have n rays to choose from, then the number
of possible angles nC2, which equals n! / [ 2 (n-2)! ]. Look up combinations using our
quick search or topics list for more explanation.

Stephen La Rocque.

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