The area is maximized when half the fence is used parallel to the building, and the other half is split between the ends and partitions.
Each of the 4 kennels is (105/4)' long by (105/5)' wide, that is ...
.. 26.25 ft long by 21 ft wide.
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Let x represent the length of fence used parallel to the building. Then the total area is
.. A = x*(210 -x)/5
This is the equation of a parabola with its vertex at x=105, halfway between the zeros at x=0 and x=210.