Transformations

Question 1

How do you determine a line of reflection?

Answer 1

perpendicular bisector of the segments between a pre-image and it’s image

Question 2

How to find an image point with a given pre image point and LOR

Answer 2

1. take equation of given LOR
2. find the equation of a perpendicular line that goess through the pre image point
3. solve the two equations as a system of equations (to find intersection
4. find the change between the pre image and the intersection (for both x and y)
5. apply that change to the intersection to find the image

Question 3

What is the rule for rotations of 90 degrees, 180 degrees, 270 degrees, and 360 degrees ABOUT THE ORGIN

Answer 3

Pre image (x, y)
90 degrees (-y, x)
180 degrees (-x, -y)
270 degrees (y, -x)
360 degrees (x, y)

Question 4

rotations not about the orgin (90, 180, 270 degrees)

Answer 4

find the slope from the point of rotation to the pre image

slope = x/y

for 90 degrees, apply -y/x to the point of rotation

for 180 degrees apply -x/-y to the point of rotation

for 270 degrees apply y/-x to the point of rotation

REMEMBER that slope is opposite of order of points (sort of like y/x)

Question 5

Translation notation

Answer 5

T[vector] (preimage)

Question 6

Reflection notation

Answer 6

R linear equation (pre image)

Question 7

Rotation notation

Answer 7

r(degree, point of rotation) (pre image)