Please help me with all of these, with explanation

Which statement is true 1.the pythagorean theorem can be used to find the missing side of any triangle 2.the pythagorean theorem can be used to find the missing side of any polygon 3. the pythagorean theorem can be used to find the missing side of any right triangle 4.the pythagorean theorem can be used to find the missing side of any isosceles triangle

Complete the standard form of the equation that represents the quadratic relationship displayed above, where a, b, and c are rational numbers.

Abox holds 500 paperclips. after a week on the teacher's desk 239 paperclips remained. how many paperclips were used?