Lesson Plan #41. Class: Geometry Date: Monday December 17 th, 2018

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1 Lesson Plan #41 Class: Geometry Date: Monday December 17 th, 2018 Topic: Rotations Objectives: 1) Students will be review line and point symmetry. 2) Students will be able to define a rotation. 3) Students will know the properties preserved under a rotation. 4) Students will be able to perform a rotation of a figure about a point using a protractor. 5) Students will be able to find the measure of an angle of rotation using a protractor. 6) Students will be able to determine the center of rotation using a compass and straight-edge. Aim: How do we perform a rotation? HW#41: On a separate sheet of loose-leaf paper, write a proper HW heading, then copy and paste the two triangles below. ABC was rotated about a point producing image A'. 1) Via construction, find the center of rotation and label it P. 2) With a protractor, find how many degrees ABC was rotated? Do Now: 1) More lines of symmetry questions at: 2) More point symmetry questions at:

2 PROCEDURE: Write the Aim and Do Now Get students working! Take attendance Give Back HW Collect HW Go over the Do Now Assignment #1: What needs to be done to the picture at right so we can see it upright? How many degrees? (Teacher: Rotate figure so that it can be viewed upright) Online Activity: Let s go to to see an animation of a rotation Definition: A rotation is a transformation that turns a figure a certain number of degrees about a fixed point called the center of rotation. Sample Test Question: 1) What is the center of rotation? Name an angle of rotation? Measure an angle of rotation (measure with your protractor). What is the degree measure? Is the image of the triangle congruent to the pre-image? Why? Is orientation preserved? Observations: A rotation is a basic rigid motion transformation. A rotation is an isometry. Properties preserved (invariant) under a rotation: 1. distance is preserved (lengths of segments are the same) 2. angle measures (remain the same) 3. parallelism (parallel lines remain parallel) 4. colinearity (points stay on the same lines) 5. midpoint (midpoints remain the same in each figure) 6. orientation (lettering order remains the same), more specifically a direct isometry. Sample Test Questions: 1)

3 2) Identify the transformations show below A) B) 3) Assignment #2: Exercise #1: Rotate ABC o 75 counterclockwise about point P using a protractor. Exercise #2: Quadrilateral ABCD has been rotated clockwise producing image quadrilateral A ' D' A) Which point is the center of rotation? B) Find the measure of an angle of rotation.

4 Exercise #3: Quadrilateral ABCD has been rotated about point E. How many degrees has quadrilateral ABCD been rotated? Assignment #3: Exercise #4: Find center of rotation, an angle of rotation, and the number of degrees rotated for the rotation shown below.

5 Final Summary: A rotation turns a figure through an angle about a fixed point called the center. A positive angle of rotation turns the figure counterclockwise, and a negative angle of rotation turns the figure in a clockwise direction. A rotation is a basic rigid motion transformation. A rotation is an isometry. Properties preserved (invariant) under a rotation: 1. distance is preserved (lengths of segments are the same) 2. angle measures (remain the same) 3. parallelism (parallel lines remain parallel) 4. colinearity (points stay on the same lines) 5. midpoint (midpoints remain the same in each figure) 6. orientation (lettering order remains the same), more specifically a direct isometry. If enough time Sample Test Questions: 1) What kind of transformation could it be? 2) 3) 4)

6 H.O.T Question A) Find, via construction, the center of rotation; label it P. B) Find the measure of the angle of rotation. C) State a relationship between ABC and its image A'. Justify. D) Reflect ABC through point A, creating AB"C" E) Reflect A' through A ' creating A' '' F) Find the sum of the measures of the exterior angles of quadrilateral A ' B" ' ' G) What relationship exists between A ' and B ' ' '? H) Via construction, locate the circumcenter of ABC. Label it M. I) Via construction, locate the centroid of A'. Label it N. HOTTER QUESTION Rotate triangle ABC clockwise by m ABC about point C.