Use the graph to determine the domain and range of the relation, and whether the relation is a function

Acircle has a circumference of 2 pi cm. which statement about the circumference and area is true? a comparison of the area and circumference is not possible since the area cannot be determined. the numerical values of the circumference and area of the circle are equal. the numerical value of the circumference is greater than the numerical value of the area. the numerical value of the circumference is less than the numerical value of the area.

Just tell me how to set up the equation.

Which of the following parabolas opens up?