Unit 7, Quiz 1 Review

Unit 7, Quiz 1 Review

• ​You have an unlimited number of attempts to complete this review and practice for your quiz tomorrow.

• The highest score will count for your grade on AERIES.

From the Equation

• Make the signs on h and k OPPOSITE to get the center

• Take the SQUARE ROOT of r² to get the radius

• If you don't SEE h or k, then that means the coordinate is ZERO.

Multiple Choice

In the equation $$(x-3)^2+(y-2)^2=16$$ , the center of the circle is...

• (3,2)

• (-3, -2)

• (-2, -3)

• (2, 3)

Multiple Choice

In the equation $$(x-3)^2+(y-2)^2=16$$ , the radius of the circle is...

• 16

• 32

• 8

• 4

Multiple Choice

In the equation $$x^2+(y+5)^2=10$$ , what is the center?

• (1, 5)

• (-1, -5)

• (0, 5)

• (0, -5)

To Write the Equation

• Make the signs on the center OPPOSITE before you plug them in for h and k.

• SQUARE the radius (multiply it by itself) before you plug it in for r²

• If you were given the diameter, then divide that by 2 to get the radius. And then square it before you plug it in as r²

Multiple Choice

Write the equation of a circle with center (7, 0) with radius 3.

• $$(x-7)^2+y^2=9$$

• $$x^2+(y-7)^2=9$$

• $$(x-7)^2+y^2=3$$

• $$x^2+(y-7)^2=3$$

Multiple Choice

The diameter of a circle has length 12. The center is at (-5, 2). Give the equation of the circle.

• $$(x-5)^2+(y+2)^2=6$$

• $$(x+5)^2+(y-2)^2=36$$

• $$(x+2)^2+(y-5)^2=6$$

From a Graph

• Find the coordinates of the center. Make the signs on both of them OPPOSITE before you plug them in for h and k.

• Find the radius by counting the distance from the center out to the edge of the circle. Then SQUARE the radius before you plug it in for r²

  
  

Multiple Choice

What is the equation for this circle?

• $$(x+1)^2+(y+1)^2=9$$

• $$x^2+y^2=9$$

• $$x^2+y^2=6$$

• $$x^2+y^2=3$$

Multiple Choice

What is the equation of the circle?

• $$\left(x-2\right)^2+y^2=3$$

• $$\left(x+2\right)^2+y^2=9$$

• $$\left(x-2\right)^2+y^2=9$$

• $$\left(x+2\right)^2+y^2=3$$

Multiple Choice

What is the equation of the circle?

• $$\left(x+1\right)^2+\left(y-1\right)^2=2$$

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

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

• $$\left(x-1\right)^2+\left(y+1\right)^2=2$$

Equations of Parabolas

Multiple Choice

What direction does this parabola open?

$$y=\frac{1}{2}x^2$$  

• Up

• Down

• Left

• Right

Multiple Select

Which equation has a parabola facing up?

• $$y=4x^2-5$$

• $$y=-4x^2-5$$

• $$x=4y^2-5$$

• $$x=-4y^2-5$$

Multiple Select

Which equation has a parabola facing down?

• $$y=4x^2-5$$

• $$y=-4x^2-5$$

• $$x=4y^2-5$$

• $$x=-4y^2-5$$

​When |a| is less than 1, the graph gets wider.

​When |a| is greater than 1, the graph gets more narrow (thin).

Multiple Choice

Explain the transformation

$$y=4(x+5)^2+3$$

• Wider, right 5, up 3

• Thinner, left 5, up 3

• thinner, right 5 up 3

• wider, left 5, up 3

Equations of Parabolas

Multiple Choice

Since the parabola opens right, then the a-value has to be...

• positive

• negative

Multiple Choice

$$x=-8\left(y-4\right)^2+1$$
What direction does this parabola open?

• up
• down
• left
• right

Multiple Choice

Which direction does this parabola open/face?

$$x=-\left(y-1\right)^2+5$$

• Up
• Down
• Left
• Right

Multiple Choice

In which direction does this parabola open?
$$x=-2\left(y-3\right)^2+7$$  

• $$right$$  

• $$left$$  

Remember your quiz is tomorrow and will cover the first 3 sections of Unit 7.