8th Grade Math - Lines and Angles

This post explains and gives 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

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Instruction

Students learn basics of geometrics proofs, starting with angles created by parallel lines cut by a transversal and complementary and supplementary angles.

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STAAR Practice

Between 2016 and 2025 (including redesign practice), this supporting standard has been tested 7 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.

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To view all the posts in this 8th grade TEKS review series, click here.