jmc

A $12^{\prime \prime }$-diameter pizza and a $16^{\prime \prime }$-diameter pizza are each cut into eight congruent slices. Jane ate three slices of the $12^{\prime \prime }$ pizza. Mark ate three slices of the $16^{\prime \prime }$ pizza. How many more square inches of pizza did Mark eat than Jane? Express your answer as a common fraction in terms of $\pi$.