This post explains and give practice opportunities related to TEKS 8.8D:
use informal arguments to establish facts about the angle sum and exterior angle of triangles, the angles created when parallel lines are cut by a transversal, and the angle-angle criterion for similarity of triangles
Students learn basics of geometrics proofs, starting with angles created by parallel lines cut by a transversal and complementary and supplementary angles.
Between 2016 and 2021, this supporting standard has been tested 4 times on the STAAR test. Videos explaining the problems can be found below. If you'd rather take a quiz over these questions, click here. The videos below are linked to the questions in the quiz as answer explanations after the quiz is submitted.
To view all the posts in this 8th grade TEKS review series, click here.