8.G.1.a Determine and use the relationships of the interior angles of a triangle to solve for missing measures.
8.G.1.b Identify and apply geometric properties of parallel lines cut by a transversal and the resulting
corresponding, same side interior, alternate interior, and alternate exterior angles to find missing measures.
8.G.2.a Perform and describe positions and orientation of shapes under single transformations including rotations
in multiples of 90 degrees about the origin, translations, reflections, and dilations on and off the coordinate plane.
8.G.2.b Determine if two-dimensional figures are congruent or similar.
8.G.2.c Perform and describe positions and orientations of shapes under a sequence of transformations on and off the coordinate plane.
Transformation
A change that moves, flips, turns, or changes the size of a figure to create a new figure.
Translation
A transformation that slides a figure without turning, flipping, or changing its size.
Image
The new figure created by a transformation.
Reflection
A transformation that flips a figure across a line, creating a mirror image.
Line of Reflection
The line across which a figure is reflected.
Rotation
A transformation that turns a figure around a fixed point.
Angle of Rotation
The number of degrees a figure is turned during a rotation.
Center of Rotation
The fixed point around which a figure rotates.
Congruent Figures
Figures that have the same size and same shape. Their corresponding sides and angles have equal measures.
Dilation
A transformation that changes the size of a figure while keeping its shape the same.
Scale Factor
The number used to multiply the dimensions of a figure to find the dimensions of its image after a dilation.
Enlargement
A dilation that makes a figure larger. The scale factor is greater than 1.
Reduction
A dilation that makes a figure smaller. The scale factor is between 0 and 1.
Similar
Figures that have the same shape but not necessarily the same size. Their corresponding angles are congruent and their corresponding side lengths are proportional.
Transversal
A line that intersects two or more other lines at different points.
Corresponding Angles
Angles that are in the same relative position when a transversal crosses two lines.
Alternate Interior Angles
A pair of angles that are between two lines and on opposite sides of the transversal.
Same-Side Interior Angles
A pair of angles that are between two lines and on the same side of the transversal.
Remote Interior Angles
The two interior angles of a triangle that are not adjacent to a given exterior angle.
Exterior Angle of a Triangle
An angle formed when one side of a triangle is extended. It is outside the triangle and forms a linear pair with one of the triangle's interior angles.