Adam could fit w action figures on each shelf in his room. His room has could hold x action figures. How many total shelves did his room have?
Adam could fit w action figures on each shelf in his room.

This means that if we have w shelves, we can fit w * w action figures in total. 

His room has could hold x action figures.

This means that if we have x shelves, we can fit x * x action figures in total. 

How many total shelves did his room have?

This means that we need to solve for x in the equation x * x = w * w.