standard_description: Use informal arguments to establish facts about the angle sum and exterior angle of triangles, about the angles created when parallel lines are cut by a transversal, and the angle-angle criterion for similarity of triangles. For example, arrange three copies of the same triangle so that the sum of the three angles appears to form a line, and give an argument in terms of transversals why this is so.
problem_activity: Reflect angle
$${\angle FGH}$$
over
$${\overleftrightarrow{JK}}$$
.
Describe the relationships between the line segments and angle of the image and the pre-image.
Describe the relationship between the distance of corresponding points to the line of reflection.
Describe the relationship between the line of reflection and line segments formed by corresponding points.
[IMG]


aligns: no