Virginia SOL 8.MG.3

8.MG.3 is a Standards of Learning standard. These are the knowledge and skills expectations under it.

• 8.MG.3.a

  Given a preimage in the coordinate plane, identify the coordinates of the image of a polygon that has been translated vertically, horizontally, or a combination...

• 8.MG.3.b

  Given a preimage in the coordinate plane, identify the coordinates of the image of a polygon that has been reflected over the x- or y-axis

• 8.MG.3.c

  Given a preimage in the coordinate plane, identify the coordinates of the image of a polygon that has been translated and reflected over the x- or y-axis or ref...

• 8.MG.3.d

  Sketch the image of a polygon that has been translated vertically, horizontally, or a combination of both.

• 8.MG.3.e

  Sketch the image of a polygon that has been reflected over the x- or y-axis.

• 8.MG.3.f

  Sketch the image of a polygon that has been translated and reflected over the x- or y-axis, or reflected over the x- or y-axis and then translated.

• 8.MG.3.g

  Identify and describe transformations in context (e.g., tiling, fabric, wallpaper designs, art).

01

What Students Need to Do

Students find and graph polygon coordinates after horizontal or vertical translations and reflections across either coordinate axis. They apply two transformations in a stated order and describe transformations seen in designs.

02

What Mastery Looks Like

Students accurately calculate and plot every image vertex after one or more transformations. They name the direction and distance of a translation and the axis of reflection. They can explain each coordinate change.

03

Common Misconceptions

Students may change both coordinate signs when reflecting across only one axis. They may add a translation to one vertex but not the others. They may also ignore that changing the order of two transformations can change the final image.

04

How to Assess It

Exit ticket: Triangle A(1, 2), B(4, 2), and C(2, 5) moves left 3 and up 1, then reflects across the y-axis. List and sketch the final coordinates.

1. 01

   Plot a polygon on graph paper, trace it on patty paper, then slide or flip the tracing and record the new vertices.

2. 02

   Give two transformation sequences and ask, “Will they land in the same place?” Students justify their answers with coordinates and sketches.

3. 03

   Play Transformation Relay: teams draw a card, apply its translation or reflection, and pass the new coordinates to the next player.

4. 04

   Analyze a wallpaper border, mark repeated shapes, and describe each translation or reflection using direction, distance, and axis.

• 6.MG.4

  The student will determine congruence of segments, angles, and polygons.

• 7.MG.4

  The student will apply dilations of polygons in the coordinate plane.