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MOTION IN GEOMETRY: TRANSFORMATIONS. 1.6 Geometry. CONGRUENCE. Figures that match exactly (SHAPE & SIZE) are said to be congruent. TRANSFORMATIONS. The movement of a figure in a plane from its original position, the preimage, to a new position, the image. RIGID TRANSFORMATIONS
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MOTION IN GEOMETRY:TRANSFORMATIONS 1.6 Geometry
CONGRUENCE • Figures that match exactly (SHAPE & SIZE) are said to be congruent
TRANSFORMATIONS • The movement of a figure in a plane from its original position, the preimage, to a new position, the image. • RIGID TRANSFORMATIONS • Transformations that do not change the size or shape of a figure.
Preimage The figure before you move it. Usually named with letters Example: A, B, AB… Image The figure after it has been moved Usually named with a letter and a prime symbol (apostrophe) Example: A’, B’, A’B’… Transformations
3 Main Types of Transformations • TRANSLATIONS • ROTATIONS • REFLECTIONS
TRANSLATIONS • Every point of a figure moves in a straight line, and all points move the same distance and in the same direction.
ACTIVITY 1 • Translating an image
ROTATIONS • Every point of a figure moves around a given point known as the center of rotation. All points move the same angle measure.
ACTIVITY 2 • Rotating an image
REFLECTIONS • A line plays the role of a mirror, and every point in a geometric figure is “flipped” across the line.
ACTIVITY 3, PART 1 • The Reflection of a Point
If a point is reflected across a line, then the line is the ______________ ____________ of the segment that connects the point with its image.
ACTIVITY 3, PART 2 • The Reflection of a Triangle
If a triangle is reflected across a line, then the reflected image of the triangle is ____________ to the original triangle
Glide Reflection • A combination of a translation and a reflection.