What's the Translation?

By Marilyn Mears on Apr 24, 2017

Students will demonstrate understanding of translations in geometry by using coordinate grids and rules.

  • Students should know how to plot points on a coordinate grid and also be able to give the ordered pairs for points already on a graph.

Materials

  1. Graph board or cardboard with push pinsAngleg
  2. "Anglegs" www.hand2mind.com
  3. iPad with graphing app
  4. Orion TI-84 Talking Graphing Calculator

Procedure

  1. Using “Anglegs” (www.hand2mind.com), ask students to create any simple shape they want. (We don’t want any decagons right now!) Put the shape on a tray. Have students demonstrate a translation by simply moving the shape from the left side of the tray to the right. Make sure they don’t rotate the shape.
  2. Now take a piece of black-lined graph paper, braille graph paper, or a graphing app on the iPad and plot your shape on the graph using push pins, magnets, or sticky dots. Label your shape. Write the coordinates of all your points.
  3. Now graph the image of your shape when you translate 1 unit to the right and 5 units up. Write the coordinates of your shape’s new position and label it as prime (so ∆ABC becomes ∆A’B’C’)
  4. Try these after presenting the shapes on a graph.
  5. Graph the image of ∆ABC [ A(2,4), B(4,4), C(4,1) ] after a translation of 2 units up and 3 units down.
  6. Graph the image of PQRS [ P(2,2), Q(6,2), R(2,2), S(6,-1)] after a translation of 3 units down and 5 units up.
  7. Present the rule for translation. (x,y) → (x + a), (y + b)

collage of translations

 

Variations

  • If students are using the Talking Graphing Calculator or the iPad, make sure they understand how the translation is working on a graph.
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