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OAT Lesson 22: Calculating Slopes

Last updated over 2 years ago
14 questions
Develop Understanding
Today's Learning Goal: (G8, U3,L10)
  • Create a graph of a line using a verbal description of its features.
  • Describe (orally) the graph of a line using formal or informal language precisely enough to identify a unique line.
  • Generate a method to find slope values given two points on the line.
Today's Materials:
  • Laptop
  • Laptop charger
  • Pen/Pencil/Paper/Expo Marker (optional)
Please complete the Jump Start (activator). You have 5 minutes before we review. This is independent it should be silent.
Reminders:
1. Ready for class
2. No cellphones
3. Volume must be low.
4. Read and follow all directions
5.) Take your bag off and immediately begin the Activator.

JUMP START: Intger Operations Review - ( 5min)

Required
1

Find values for a and b that make each side have the same value:

Required
1

Find values for a and b that make each side have the same value:

Required
1

Find values for a and b that make each side have the same value:

Launch: Deriving Slope formula - (10 min)

I do (question
We do (question
You do (question)
Required
0

Calculate the slope of the graph:

Required
0

Required
1

Required
1

Calculate the slope (m) of a line with points:

(Assume the points are positive.)

Activity 1: Towards a More General Formula

Required
0

Plot the points (1,11) and (8,2)

  • Click the graph tab.
  • Click on the graph background to add a point. Add two points to create a graph. Drag a point or type in x and y coordinates to edit its position. Click on a point to delete it.
Required
0

Without calculating, do you expect the slope of the line through (1,11) and (8,2) to be positive or negative? How can you tell?

Required
0

Calculate the slope of the line.

Required
1

Given a fixed point (1,3) with slope
(m) = 2. Use the slope formula we derived in the launch to find the equation of the line.
(Hint solve for y)

Activity 2: Making Designs

(Groups of 2)

Instructions for Designers:
  1. Look at the design silently and think about how you could communicate what your partner should draw. Think about ways that you can describe what a line looks like, such as its slope or points that it goes through.
  2. Describe each line, one at a time, and give your partner time to draw them.
  3. Once your partner thinks they have drawn all the lines you described, only then should you show them the design.
Instructions for Constructers:
  1. Listen carefully as your partner describes each line, and draw each line based on their description.
  2. You are not allowed to ask for more information about a line than what your partner tells you.
  3. Do not show your drawing to your partner until you have finished drawing all the lines they describe.
Required
0

Does your graph match your partners design? If so, what strategy did you use? If not how come?
Turn in your paper copy or upload a picture.

Lesson Synthesis: - (5 min)

Required
0

What information do you need to know exactly where a line is?

If you know the coordinates of two points on a line, how can you tell if it has a positive or negative slope?

Cool Down: Different Slopes - (5 min)

Required
4

Find the slope of the line that goes through:
  1. (0,5) and (8,2)
  2. (-2,1) and (6,1)
  3. (-3,-2) and (-1,-5)

Closure Questions:

How do we calculate slope?
What variable do we use to define slope? y-intercept?
Can we find the slope of a line with one point?
What is the y-intercept?
Name the three formulas to a line.