Solve for the missing lengths in the sets of similar figures below.

1. $ΔABC\simΔOPQ$          

   Hint (a):

   $\frac{6}{f} = \frac{4}{6}$

   Answer (a):

   $f=9$

2. $EFGHI\sim STUVW$      

   Hint (b):

   $\frac{24}{20} = \frac{g}{15}$

3. $JKLM\sim WXYZ$       

   Hint (c):

   Use the same method as parts (a) and (b).

4. Specify a sequence of transformations to map $ΔABC$ onto $ΔOPQ$ in part (a).