Parabola A Value

How do we define a parabola using its focus and directrix?

• A parabola is the set of all points that are the same distance from a single point, called the focus of the parabola, and a line, called the directrix of a parabola.

• A parabola is the set of all points that have a greater y value than a single point, called the focus of the parabola, and a lesser x value than a single point, called the directrix of the parabola.

• A parabola is a circle with a center point called the focus of the parabola, and a line from the center of the circle to the circle called the directrix of the parabola.

• A parabola is a square in which the center of the square is called the focus of the parabola, and the length of one side of the square is called the directrix of the parabola.

What is the standard equation of a parabola that opens right and whose vertex is at the origin?

A positive parabola opens ___

• up

• down

• sideways

• seriously?

What is the vertical line that divides the parabola into two equal parts?

• parabola

• vertex

• axis of symmetry

• unicorns

What is the standard equation of a parabola if the vertex is at the origin and the focus is located

4 units above the vertex?

If the focus of a parabola is (0, –3) and its directrix is y = 3, then its equation is

• x² = –12y
• x² = 12y
• y²= 12 x
• y²= -12 x

Find the standard form of the equation of the parabola whose focus (0, 4) and a directrix y=-4.

• y = (1/16)x²
• y² = 4x
• y² = 16x
• y = (1/4)x²

What is the equation of this parabola?

• x² = -3y

• y² = 12x

• x² = -12y

• y² = 3x

What is the directrix of this parabola?

• x = -3

• y = -3

• x = 3

• y = 3

What is the standard form of the equation of the parabola with Focus: (0, 7) and the vertex at the origin?