Understanding Parabolas

What is the definition of a parabola?

• A set of points equidistant from a fixed point

• A set of points equidistant from a fixed line

• A set of points equidistant from two fixed points

• A set of points equidistant from a fixed point and a fixed line

In the standard form of a parabola with a vertical axis of symmetry, what does the equation x^2 = 4cy represent?

• A parabola opening to the left

• A parabola opening downwards

• A parabola opening upwards

• A parabola opening to the right

For a parabola with a horizontal axis of symmetry, which variable is squared in its equation?

• x

• y

• Both x and y

• Neither x nor y

What is the axis of symmetry for a parabola that opens to the right or left?

• x = c

• x = 0

• y = 0

• y = c

Given the equation x^2 = 20y, what is the value of c?

• 5

• 10

• 4

• 20

If a parabola's equation is x = -2y^2, in which direction does it open?

• Downwards

• To the left

• Upwards

• To the right

What is the directrix of a parabola with focus (0, 5) and vertex at the origin?

• x = -5

• x = 5

• y = -5

• y = 5

For a parabola with focus (0, 3) and vertex at the origin, what is the value of c?

• 1

• 0

• -3

• 3

What is the equation of a parabola with focus (0, -3) and vertex at the origin?

• y = -1/12 x^2

• y = 1/12 x^2

• x = -1/12 y^2

• x = 1/12 y^2

If a parabola opens downwards, what can be said about the value of c?

• c is positive

• c is undefined

• c is negative

• c is zero