How are Transformations Named?
All transformations use the same method for referring to the original image
and naming the transformed image. The original image is called the preim-
age and the new figure is called the image. When a point undergoes a trans-
formation, it keeps the same name, but is followed by a prime mark ('). For
example, after point Q is transformed, it becomes Q', which is said, “Q
prime.” Look at the transformation of polygon ABCD in the following fig-
ure. Notice that the image it creates is named A'B'C'D'.
Transformation
y
A
ABCD Is the Preimage. A'B'C'D' Is the Image.
B
C
D
A'
B'
C'
D'
501 Geometry Questions