Using the State Curriculum: Mathematics, Grade 8

 Lesson Seeds: The lesson seeds are ideas for the indicator/objective that can be used to build a lesson. Lesson seeds are not meant to be all-inclusive, nor are they substitutes for instruction.
 Standard 2.0 Knowledge of Geometry Topic E. Transformations Indicator 1. Analyze a transformation on a coordinate plane Objective a. Identify, describe, and plot the results of multiple transformations on a coordinate plane

Materials needed

Coordinate grids for each student, transparency coordinate grid (teacher), worksheets with polygons (basic polygons, i.e., square, rectangle, triangle) for each student, colored transparency polygons (square, rectangle, triangle, pentagon) (teacher).

Activity

Make sure your polygons fit exactly on the grid paper i.e. the coordinates of their vertices are integral. One way to do this is to color shapes on one copy of the grid, cut them out, and paste them onto a worksheet.

• Model the different transformations for the students using an overhead copy of the materials. The class should initially agree on a "starting point" for the square and shade that shape on their coordinate grid (later this starting point can be left to the discretion of the students). Working in pairs, student #1 performs one (and later two) transformation(s) with the polygon. The other student using the shaded starting point, the new position of the polygon must identify — using the terms translation, rotation, and reflection — what type of transformation has taken place, and the coordinates of the image. The "identifying" student must be able to justify his/her answer by demonstrating the transformation upon the polygon.

• The game can also be played by having one student describe a transformation, and the other move the polygon.

• As students improve at the game you may give them additional polygons to transform. They will then incorporate two or more transformations on the polygons.

Note: Students should be made aware that the results of some transformations can look alike, i.e. a translation of a square, might appear to also be a reflection of that same square.