How do I find the correct answer and what is the correct answer

What is the name used to describe a graph where for some value of x, there exists 2 or more different values of y?

Acylinder and its dimensions are shown. which equation can be used to find v, the volume of the cylinder in cubic centimeters?

Rhombus adef is inscribed into a triangle abc so that they share angle a and the vertex e lies on the side bc . what is the length of the side of the rhombus if ab=c, and ac=b.