Help asap! If you can possibly do it step by step! please & thank you :)

The circumference of a circle is 5 pi cm. what is the area of the circle?

Evaluate-27 ^4/3/8 a) - 81/16 b) 81/16 c) 16/81

Brian, chris, and damien took a math test that had 20 questions. the number of questions brian got right is 14 more than the number of questions chris got right. damien correctly answered 2 less than the number of questions chris answered correctly. if brian and damien have the same score, which statement is true?