Composition
Pacing:This lesson should take one class period
Goal:This lesson introduces students to the concept of composition. Composition is the process of applying two
(or more) operations to an object. This concept is also in Advanced Algebra.
Look Out! Students can get easily confused when applying compositions. They may attempt to perform the
composition from left to right, as in reading a sentence. Point out to the students they must begin with the object
and, according to the order of operations, should perform the operation occurring within the parentheses first.
Notation! Composition notation can take two forms. To write the reflection ofABCDover linemfollowinga
reflection over linen, you could:
A. Writern◦rm(ABCD)
B. Writern(rm(ABCD))
The lowercase[U+0080][U+009C]r[U+0080][U+009D]stands for reflection and the subscript refers to the reflect-
ing line.
Watch Your Feet!Your feet are a prime example of glide reflections. When you walk, one foot is translated above
the other and are reflected about your body’s center line.
Tessellations
Pacing:This lesson should take one class period
1.12. Transformations