Answer:
Length = 13 cm.
Explanation:
If the length is L and the width is W we have the system:
2L + 2W = 32
LW = 39
From the first equation:
L + W = 16 and
L = 16 - W
Substitute this in the second equation:
W(16 - W) = 39
16W - W^2 = 39
W^2 - 16W + 39 = 0
(w - 13)(W - 3) = 0
W = 13, 3
As W < L, W must be 3 because L = 16-13 = 3 does not make sense.
So Length = 16 - 3 = 13.