5.3.5 Parabolas Review

Look at the graph of the parabola shown. Select the choice that states a possible focus and directrix for the graph.

• Focus (-4, 4)

  Directrix x=8

• Focus (-4, 4)

  Directrix y=8

• Focus (4, -4)

  Directrix x=8

• Focus (4, -4)

  Directrix y=8

What is the vertex of the parabola represented by the following equation?  $x=\frac{1}{6}\left(y-4\right)^2-8$  

• (-4, -8)

• (4, -8)

• (-8, 4)

• (-8, -4)

What is the focus of the parabola represented by the following equation?  $y=-\frac{1}{16}\left(x+4\right)^2+2$  

• (0, 2)

• (0, -2)

• (-4, -2)

• (-4, 2)

What is the directrix of the parabola represented by the following equation?  $y=-\frac{1}{16}\left(x+4\right)^2+2$  

• x=-6

• y=-6

• x=6

• y=6

Select the equation that represents a parabola in vertex form with vertex (3, -2) and directrix x=-6

• $x=\frac{1}{36}\left(y+2\right)^2+3$

• $y=\frac{1}{36}\left(x-3\right)^2-2$

• $x=-\frac{1}{36}\left(y+2\right)^2+3$

• $y=-\frac{1}{36}\left(x-3\right)^2-2$

Select the equation that represents the parabola graphed on the coordinate plane.

• $x=-\frac{1}{4}\left(y+2\right)^2-4$

• $y=-\frac{1}{4}\left(x-4\right)^2+2$

• $x=-\frac{1}{4}\left(y-2\right)^2+4$

• $y=-\frac{1}{4}\left(x+4\right)^2-2$

The cross section of a satellite dish is a parabola. Suppose a satellite dish receiver is located at the focus of the cross section, 10 feet in front of the vertex.

Assume the vertex is at the origin and that the parabola is concave left. Write an equation that represents the cross section of a satellite dish.

• $x=\frac{1}{40}y^2$

• $y=\frac{1}{40}x^2$

• $y=-\frac{1}{40}x^2$

• $x=-\frac{1}{40}y^2$

Select the graph of the parabola represented by the following equation.   $y=\frac{1}{2}\left(x-3\right)^2+1$  

• 
• 
• 
• 

Formula for vertical parabolas (open up or down):

•  $y=\frac{1}{4p}\left(x-h\right)^2+k$  

•  $x=\frac{1}{4p}\left(y-k\right)^2+h$  

Formula for horizontal parabolas (open left or right):

•  $y=\frac{1}{4p}\left(x-h\right)^2+k$  

•  $x=\frac{1}{4p}\left(y-k\right)^2+h$