MA19.8.25

Mathematics (2019) Grade(s): 8

MA19.8.25
Analyze and apply properties of parallel lines cut by a transversal to determine missing angle measures.

Unpacked Content

Knowledge

Students know:

That a straight angle is 180 degrees
That a triangle has three interior angles whose sum is 180 degrees.
The definition of transversal.
How to write and solve two-step equations.

Skills

Students are able to:

Make conjectures about the relationships and measurements of the angles created when two parallel lines are cut by a transversal.
Informally prove that the sum of any triangle's interior angles will have the same measure as a straight angle.

Understanding

Students understand that:

Missing angle measurements can be found when given just one angle measurement along a transversal cutting through parallel lines.
Every exterior angle is supplementary to its adjacent interior angle.
Parallel lines cut by a transversal will yield specific angle relationships that are connected to the concepts of rigid transformations (i.e. vertical angles are reflections over a point. corresponding angles can be viewed as translations).
The sum of the interior angles of a triangle is 180 degrees.

Vocabulary

Transversal
Corresponding Angles
Vertical Angles
Alternate Interior Angles
Alternate Interior Angles
Supplementary
Adjacent

Aligned Learning Resources

Angles, Angles, and More Angles

Design by Adaptive Theme