How to translate a problem into an equation when dealing with perimeter and trying to find the length?

What basic trigonometric identity would you use to verify that csc x sec x cot x = csc^(2)x

Charles is on a 8 1/2 mile bike ride. he stops for a rest after he’s gone 5 2/5 miles. how much farther does he still have to go?

2. explain in words how you plot the point (4, −2) in a rectangular coordinate system.