Final answer:
A simile is used to compare Cinderella's slippers to the sun.
Step-by-step explanation:
The sentence 'Cinderella's slippers were as shiny as the sun' is a simile. It is comparing Cinderella's slippers to the sun. The simile uses the word 'as' to make the comparison. Similes use 'like' or 'as' to compare two different things.
Learn more about Similes and metaphors