Question 1065599

Perimeter:  2l + 2w = 52m
                  w = l + 12           (usually the length is the longer side)

Substitute "l+12" for "w" from the bottom equation into the top one:
                   2l + 2(l+12) = 52
                    4l + 24 = 52
                             4l = 28 —>   l=7  —> w=12+7=19

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 Ans:    length is 7m, width is 19m
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 Check:
            Perimeter =  2*7m + 2*19m = 14m + 38m = 52m  (ok)