Can someone tell me the answer plz(answer 9)I’ll give brainlist and points

How do you write something in scientific notation?

Iknow its nothing to do with education, but what type of thing should i wrote here? ? : ) its for mcdonald's btw.

Which set of side lengths form a right side? a) 3ft,6ft,5ft b)50 in,48in,14in c)53m,48m,24m d)8cm,17cm,14cm