Use cross multiplication.
$35·100=70x\\ \quad \ 3500 = 70x$

$x= \frac{3500}{70}=50$

Use the inverse to undo.

$\left(\frac{11}{1}\right)\frac{12}{33}=\frac{m}{11}\left(\frac{11}{1}\right)$

$m=4$

Use a Giant One to find the equivalent ratio.

$\frac{x}{15}\left(\frac{?}{?}\right)=\frac{12}{75}$

$\frac{x}{15}\left(\frac{5}{5}\right)=\frac{12}{75}$

$x=2.4$

Try using one of the methods presented in either part (a), (b), or (c).