Grab vertices of a polygon undergoing reflections and rotations in the coordinate plane to determine the transformation’s type.

• Students will be able to identify the correct 2 x 2 matrix that, when multiplied to a matrix representation of a polygon, results in a polygon: • Reflected across the x-axis. • Reflected across the y-axis. • Rotated 90° about the origin. • Rotated 180° about the origin.

• rotation
• reflection
• matrix
• element
• identity

This lesson involves grabbing vertices of a polygon undergoing reflections and rotations in the coordinate plane to determine the transformation’s type. It also involves duplicating a reflection or rotation by: changing the elements of 2x2 matrices and evaluating the effects of the multiplying matrix on the polygon in the coordinate plane. As a result, students will make conjectures about the relationships between certain 2x2 matrices and their effects on the resulting transformed polygons obtained through matrix multiplication.