What is the length of the missing side?

You will get 25 points an image of a rectangular prism is shown below: part a: a cross section of the prism is cut with a plane parallel to the base. what is the name of the shape created by the cross section? explain your answer. (5 points) part b: if a cross section of the prism is cut perpendicular to the base, what would be the shape of the resulting cross section? explain your answer. (5 points)

An animal shelter has 21 puppies. if the puppies are 28% of the total dog and cat population , how many dogs and cats are in the animal shelter

How do you solve a question like this?