Unit 1, Lesson 5
Describing Transformations
Accelerated 7
5.1
Warm-up
is the image of after some transformations.
What specific information do you need to be able to solve the problem?
Student Lesson Summary
When describing a sequence of transformations, there are several pieces of information that are important to know. For a translation, we need to know distance and direction. For a rotation, we need the center of rotation, direction, and amount of rotation. For a reflection, we need a line of reflection. There is one more piece of information that is helpful though.
When we perform a sequence of transformations, the order of the transformations can be important.
Here is triangle translated up two units and then reflected over the -axis.
Triangle A B C reflected on a coordinate plane, origin O. Horizontal and vertical axis scale negative 5 to 5 by 1’s. Triangle A B C is blue and has coordinates: A(negative 2 comma 2), B(negative 1 comma 3) and C(1 comma negative 1). The green triangle has coordinates: (negative 2 comma negative 4), (negative 1 comma negative 5) and C(1 comma negative 1).
Here is triangle reflected over the -axis and then translated up 2 units.
Triangle A B C reflected on a coordinate plane, origin O. Horizontal axis scale negative 5 to 5 by 1’s. Vertical axis scale negative 5 to 5 by 1’s. Triangle A B C is blue and has coordinates: A(negative 2 comma 2), B(negative 1 comma 3) and C(1 comma negative 1). The green triangle has coordinates: (negative 2 comma 0), (negative 1 comma negative 1) and (1 comma 3).
Triangle ends up in different places when the transformations are applied in the opposite order!
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