I don’t know how to do this is 10th grade Geometry

What is the length of an with endpoints a 3,2 and b 8,14

Which sum or difference identity would you use to verify that cos (180° - ∅) = -cos ∅? a. sin (α -β) = sin α cos β – cos α sin β b. cos (α -β) = cos α cos β – sin α sin β c. cos (α -β) = cos α cos β + sin α sin β d. sin (α + β) = sin α cos β + cos α sin β

How do you find the circumfrance of a circle?