a) $\frac{9x25}{25x36}$ = $\frac{25x}{25x}$x $\frac{9}{36}$ = $\frac{1}{4}$
b) $\frac{54x35}{45x81}$ = $\frac{54.35}{45.81}$ = $\frac{1890}{3645}$ = $\frac{14}{27}$
c$\frac{15}{42}$ x $\frac{30}{45}$ x 1$\frac{5}{16}$ = $\frac{15}{42}$ x $\frac{30}{45}$ x $\frac{21}{16}$ = $\frac{9450}{30240}$ = $\frac{5}{16}$