Worked Example 1
Triangle ABC has corners A(1, 1), B(4, 1), C(1, 3). Translate it 3 across and 2 up.
Apply the same change to every pointA′(4, 3), B′(7, 3), C′(4, 5)
Check the lengthsAB was 3 units and A′B′ is still 3 units.
A quick error checkIf two image points moved by different amounts, you have made a slip.
Worked Example 2
Reflect the point P(2, 3) in the y-axis, then in the x-axis.
In the y-axisP becomes (-2, 3). The height is unchanged because the mirror is vertical.
Then in the x-axis(-2, 3) becomes (-2, -3). This time the across value stayed the same.
What just happenedTwo reflections in perpendicular mirrors gave exactly a 180 degree rotation about the origin. Two flips make a turn.
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