We know that are for the rectangle is A=a*b, where
A i area, a is one side and b is second side. It doesnt matter side we assume a or b because multiplicity is commutative.
We can substitute our data to formula
A=\(10 \frac{1}{2} *12 \frac{5}{8} = \frac{21}{2}* \frac{101}{8}= \frac{21*101}{2*8}= \frac{2121}{16}= 132.56\) [feet squared] - its the answer