Introduction
 To transform a figure (shape) means changing the size, location, and direction it faces.
 The figure before the transformation is called the preimage.
 The figure after the transformation is called the image.
 If the preimage is labeled as A, then the image would be labeled as A' (pronounced as A prime).
 There are four different types of transformation.

 Dilation
 Reflection
 Rotation
 Translation
Congruency
 Two figures are congruent if they are of the same shape and size.
 The image after rotation is congruent with the preimage.
 The symbol for congruency is ≅
Reflection
 A type of transformation that flips a figure across a line.
 It creates a mirror image (congruent figure). Congruent means the preimage and the image have the same size and shape.
Solved Examples
Question 1: What is the reflection of a point (2, 7) across the xaxis?
Solution: The reflection of a point (x, y) across the xaxis is the point (x, y). So, the reflection of the point (2, 7) will be (2, 7).
Question 2: What is the reflection of a point (3, 12) across the yaxis?
Solution: The reflection of a point (x, y) across the yaxis is the point (x, y). So, the reflection of the point (3, 12) will be (3, 12).
Question 3: Find the reflection of a point (5, 1) across the line $y=x$?
Solution: The reflection of a point (x, y) across the line $y=x$ is the point (y, x). So, the reflection of the point (5, 1) across $y=x$ will be (1, 5).
Question 4: Point $Q\left(5,2\right)$ is obtained after reflection of the point $P\left(x,y\right)$ about the xaxis as shown in the graph. Find the coordinates of the point $P$.
Solution: If point $Q\left(x,y\right)$ is reflected over the xaxis, the new point coordinate is ${Q}^{\text{'}}\left(x,y\right)$. Point $P\left(5,2\right)$ when reflected over the xaxis will produce $Q\left(5,2\right)$.
Cheat Sheet
 A reflection flips a figure over a line of reflection to create a mirror image.
 Each reflected point of the figure should have the same distance from the line of reflection on the opposite side.
 The reflected image and preimage are congruent.
 In a coordinate plane, the image can be reflected around both axes.
Blunder Areas
 Differentiate between preimage (A) and image (A').
 Differentiate between the xaxis and yaxis as the line of reflection.
 Fiona Wong
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