Understand Congruence and Similarity

Standard 8.G.1 Verify experimentally the properties of rotations, reflections, and translations (include examples both with and without coordinates).

a. Lines are taken to lines, and line segments are taken to line segments of the same length

Vocabulary for this standard: rotation, reflection, translation, line, line segment, coordinate plane, ray, angle, degree, acute angle, obtuse angle
Illustrative Math Lesson
1.2 Naming the Moves    My Slides HW
EngageNY lesson link – This appears in the second module of the EngageNY curriculum.
A rotation is the turning of an object by an angle about a fixed point.
A reflection is the operation of exchanging all points of a mathematical object with their mirror images.
A translation is a transformation consisting of a constant shift with no rotation or stretching.
A line is a straight geometric object with no thickness, extending in both directions without end (infinitely).
A line segment is a part of a line that is bounded by two distinct endpoints
A coordinate plane is a two-dimensional surface on which we can plot points, lines and curves.
A ray is a line with a single endpoint (or point of origin) that extends infinitely in one direction.
An angle is the space (usually measured in degrees) between two intersecting lines or surfaces at or close to the point where they meet.
A degree a measurement of a plane angle, defined so that a full rotation is 360 degree
An acute angle is an angle smaller than a right angle (it is less than 90 degrees)
An obtuse angle an angle of greater than 90° and less than 180°.
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