Did i get this right? if not could someone explain this to me?

Correct!
Your notes on the right side are correct, too.

Independent -- not dependent on another variable
Dependent -- dependent on another variable

The height of the plant varies because/due to of the quality/quantity of fertilizer.
So, the height is changed by the fertilizer.

Thus: height is dependent and fertilizer amount is independent.

That is correct and good job on writing out what a independent and dependant variable is.

You have 2 sides that are 2 cms and you have 6 sides that are 1/2 cm and you have 4 sides that are 1 cm. the smallest sides are 1/2 the medium sized sides are 1 and the smallest are 1/2. so to find the perimeter you have to add them all up together so your answer will be 11 cm's