Find the value of x in the figure below.

So it may be a long process, but the way i solved this problem was to first find the measure of one interior angle, then subtract that from 180 (supplementary angles) to get the measure of x.

HOW TO:

1) Find measure of ONE interior angle (keep in mind that, as labeled in the diagram, each interior angle is the same measure):note that n stands for the number of sides.
                  (n-2)180/n

                  (5-2)180/5

                  (3)180/5

                   540/5

                    108
So the measure of ONE interior angle is 108 degrees.

2) Now subtract 108 from 180 to get the measure of x.

     180-108 = 72

Thus, the measure of x is 72 degrees.

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