Since ABC is similar to DCE, you can use proportions to solve your question.
BC over AB is equal to DC over AD. Since you know this info, you can write BC over 9 is equal to 5.2 over 6.
You can use your properties to get BC equal to (5.2 over 6) times 9
BC is equal to 7.8
For the second question, you can do the same thing
CE over DE is equal to CA over BA
CE over 6 is equal to 7.2 over 9
CE is equal to (7.2 over 9) times 6
CE is equal to 4.8