Unit 3 STAAR Review

Unit 3:

Transformational Geometry

​Translations (Slide)

• A translation slides every point of a figure in the same direction.

• Left (-) Right (+)

• Down (-) Up (+)

• When you translate a shape, the new shape will be congruent (equal). The angle measures, side lengths, and size of the shape stays the same.

• What is the verbal description of the following rule (x+2, y-3) ?

• What is the algebraic rule for the following description: Left 6, Up 8

Multiple Choice

Quadrilateral BCDE is transformed according to the rule (x,y)--->(x-2, y-4) to create quadrilateral B'C'D'E'. Which statement is true?

• The side lengths of quadrilateral B'C'D'E' are twice the corresponding side lengths of quadrilateral BCDE.

• The side lengths of quadrilateral B'C'D'E' are 2 units smaller than the corresponding side lengths of quadrilateral BCDE.

• The angle measures of quadrilateral B'C'D'E' are greater than the corresponding angle measures of quadrilateral BCDE.

• The angle measures of quadrilateral B'C'D'E' are equal to the corresponding angle measures of quadrilateral BCDE.

Reflections (Flip)

• Reflections flip a shape over an axis and create a mirror image.

• In a reflection, the new shape will be congruent to the old shape.

• Reflections preserve size, angle measures, and side lengths of shape. The only thing that changes is the orientation of the shape.

• Orientation is the way a shape is facing.

Multiple Choice

Triangle ABC is reflected over the x-axis. The coordinates of Point A are (x, y). What are the coordinates of Point C', the reflected image, using an algebraic expression?

• (-x,y)

• (-x,-y)

• (x,-y)

• (y,-x)

​Rotations (Turn)

• There are 3 types of rotations

• The center of rotation is the origin (0,0) and the shape will rotate in increments of 90° degrees

• When a shape is rotated, the new shape will be congruent to the old shape. The only thing that changes is the orientation of the shape.

Multiple Choice

• (x,y)--->(-x,y)

• (x,y)--->(-x,-y)

• (x,y)--->(x,-y)

• (x,y)--->(-y,-x)

Dilations (Enlargement/Reduction)

• Dilations change the size of a shape.

• Dilations preserve angle measures and orientation of the figure.

• Size & side lengths will change but shape will be similar (proportional)

Multiple Choice

Which proportion shows the triangles are similar?