Find the missing length for the pair of similar figures.

So is it the first question or the first and second, because if its the second on two the its cut off on the pic. The answer for the first one is D. 4.5

This is what i found “an explicit formula designates the nth term of the sequence, as an expression of n (where n = the term's location). it defines the sequence as a formula in terms of n. this example is an arithmetic sequence(the same number, 5, is added to each term to get to the next term).” i hope this you for what your looking for. can you plz mark me brainliest?