let's firstly convert the mixed fractions to improper fractions, and then get their product.
[tex]\stackrel{mixed}{1\frac{1}{4}}\implies \cfrac{1\cdot 4+1}{4}\implies \stackrel{improper}{\cfrac{5}{4}} ~\hfill \stackrel{mixed}{2\frac{3}{4}}\implies \cfrac{2\cdot 4+3}{4}\implies \stackrel{improper}{\cfrac{11}{4}} \\\\[-0.35em] ~\dotfill\\\\ \cfrac{5}{4}\cdot \cfrac{11}{4}\implies \cfrac{(5)(11)}{(4)(4)}\implies \cfrac{55}{16}\implies 3\frac{7}{16}[/tex]
