Perimeter of Polygons

    The perimeter of a polygon is the measured distance all the way around the figure.  So, in order to find the perimeter of a polygon, we just add the lengths of each segment that makes up the figure.

Ex 1)    To find the perimeter of polygon ABCDE, we add the lengths of the sides.

            P = AB + BC + CD + DE + EA

         P = 3 + 5 + 4 + 5 + 7 = 24

         The perimeter of ABCDE is  24 cm.


    Ex 2)    Consider JKLM with JK = LM and KM = LJ.  For one  pair of sides JK = LM = b1, and for the other pair of sides KM = LJ = b2.

    P = JK + KL + LM + MJ

    P = b1 + b2 + b1 + b2

    P = 2b1 + 2b2

    P =  2(b1 + b2)     **You can use this formula to find the perimeter of any parallelogram.


    Now, by substituting L for b1 and W for b2, notice the simplified formula P = 2(L + W).
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