Thread: Counting

How many pairs of vertical angles are formed by five distinct lines that have a common point of intersection?


Vicky.

Thanks.

Hello, Vicky!

How many pairs of vertical angles are formed by five distinct lines
that have a common point of intersection?

Code:

                  *
          *   J   *   A   *
           *      *      *
            *     *     *
        I    *    *    *    B
  *           *   *   *           *
      *        *  *  *        *
          *     * * *     *
              *  ***  *
       H          *           C
              *  ***  *
          *     * * *     *
      *        *  *  *        *
  *           *   *   *           *
        G    *    *    *    D
            *     *     *
           *      *      *
          *   F   *   E   *
                  *

I found twenty pairs.

In the list below, means
. . and means


. . . . . . . . . . . .

. . . . . . . .

. . . .

Thank You!!!!!!!!!!!!!!!!!!!!

Vicky.