As you come in, get a slip of paper As you come in, get a slip of paper from your teacher and fill in the from your teacher and fill in the

information in the chart.information in the chart.

Be prepared to justify your answers Be prepared to justify your answers (explaining why).(explaining why).

What do you know about each equation?

What are the directrix and focus?Take a piece of patty paper andTake a piece of patty paper and

1.Fold one end making a straight line.2.Use a marker or pen to draw the line over the crease.3.Draw a dot somewhere above the line.4.Fold the line so that it intersects (passes over)the dot and make a crease.5.Continue step 4 from both sides.

  

MCC9-12.G.GPE.2How do you graph and find the important information about parabolas?

What are the directrix and focus?

A parabola is the set of all points in a plane that are the same distance

from a fixed point (called the focus), and a fixed line (called the directrix).

  

MCC9-12.G.GPE.2 How do you graph and find the important information about parabolas?

Let’s make sure you’ve got it!

What relationship does the vertex have with the focus and directrix?

The vertex is the midpoint between the focus and the directrix.

What number represents this distance?

“p” is always the distance from the focus to the vertex, or the distance from the vertex to the directrix.

What happens when the “p” value changes?

Geometer’s Sketchpad

Using your notes find the important information and graph 

 (y-3) 2 = -12 (x+2)  

Direction of the parabola, Vertex, focus, directrix, axis of symmetry

p= -3 ; h=-2; k=3 Vertical (opens left) Vertex (-2,3) Focus (-5,3) Directrix x=1 Axis of Symmetry y = 3

When will this math ever been used? A satellite dish is an

ideal example of a parabola.

Why would this shape allow the satellite to recieve the maximum signal?

Can you think of other ways parabolas are used in everyday items?

Everyday importance of parabolas.

Arched bridges are designed for stability.

Why is this important?

The Golden Gate bridge is a suspension bridge in San Francisco, California. The towers are 1280 meters apart and rise 160 meters above the road.

Suspension bridges depend on parabolically curved cables to support the weight of the road bed of the bridge.

The weight of the bridge is evenly distributed among the support cables which run parallel to the axis of symmetry, similar to the paths of rays reflected off the surface of parabolic reflectors.

Fun parabola sitings!

Work out the 4 problems (hint: we did #1 already)

EQ:  How do you find the important information and graph parabolas?