Unit 3 - Rigid Motions - Constructions

Question 1

How do you construct the line of reflection? (2)

Answer 1

1. Connect image and preimage with seg.
2. Construct Perpendicular Bisector

Question 2

How do you construct the angle of rotation? (3)

Answer 2

1. Connect image & preimage points to COR
2. Measure the value with a protractor
3. Determine + and - if angle opens left (CC +) or right (C -)

Question 3

How do you construct the center of rotation? (5)

Answer 3

1. Connect 1st preimage & image points
2. Draw Perp. Bisector of the Segment
3. Connect 2nd preimage & image points
4. Draw Perp. Bisector of the Segment
5. Intersection of Perp. Bisector is the COR

Question 4

How do you rotate a figure 60 degrees? (4)

Answer 4

1. Connect pre - image point to COR
2. Determine if you should rotate CC or C
3. Construct Equilateral Triangle
4. New point created is the image

Question 5

How do you rotate a figure 120 degrees? (4)

Answer 5

1. Connect pre - image point to COR
2. Draw semi - circle from COR
3. Determine if you should rotate CC or C
4. Draw Train Tracks from Preimage point

Question 6

How do you rotate a figure 180 degrees? (4)

Answer 6

1. Connect pre - image to COR
2. Copy segment with your compass
3. Extend that segment
4. Swing compass over to the other side of that extended line

Question 7

How do you rotate a figure 30 degrees? (3)

Answer 7

1. Draw Eq. Tri
2. At the COR angle, draw angle bisector
3. Where the bisector intersects at the line, new image

Question 8

Construct a line through the point P that is parallel to line L by rotating L 180 degrees (7)

Answer 8

1. Draw two random points (A & B) on the line
2. Draw a segment connect A and P
3. Perpendicular Bisect AP
4. MP is the COR
5. Connect the COR and B
6. Rotate B 180 degrees
7. Connect B’ and P (parallel to L)

Question 9

When graphing with slopes and rotating 90 or -90 degrees, how do you know where to graph when it is cc or c?

Answer 9

When you have your two points, and you have 90 degrees (CC), choose the one that is rotated left, or closer to your point, because -90 degrees = 270 degrees, so you will know which one SHOULD be farther (270) and the one that SHOULD NOT (90)

Question 10

Point Reflection

Answer 10

180 degree rotation

Question 11

How do you translate a segment?

Answer 11

1. Measure distance of vector
2. Copy distance on the preimage points
3. To get the direction, measure distance from starting point of vector to preimage
4. Copy that distance from the endpoint of the vector
5. Where the copy marks intersect is your image