Explain what the Diameter is and how is the radius related to it. What can the radius and Diameter help us find?

How many sides does a regular polygon have if each exterior angle measure is 45 degrees explain your answer, i really don't understand this.

Given: lines a and b are parallel and line c is a transversal. prove: 2 is supplementary to 8 what is the missing reason in the proof? statement reason 1. a || b, is a transv 1. given 2. ∠6 ≅ ∠2 2. ? 3. m∠6 = m∠2 3. def. of congruent 4. ∠6 is supp. to ∠8 4. def. of linear pair 5. ∠2 is supp. to ∠8 5. congruent supplements theorem corresponding angles theorem alternate interior angles theorem vertical angles theorem alternate exterior angles theorem

Use the distance formula to find the distance between (-3,5) and (3,1)