${\left({\displaystyle \frac{3}{4}}\right)}^2={\displaystyle \frac{3}{4}}\cdot {\displaystyle \frac{3}{4}}={\displaystyle \frac{9}{16}}\backslash left(\backslash dfrac\{3\}\{4\}\backslash right)^2=\backslash dfrac\{3\}\{4\}\backslash cdot\; \backslash dfrac\{3\}\{4\}=\backslash dfrac\{9\}\{16\}$