Lesson Plan

State the triangle angle sum theorem (the three angles of any triangle sum to 180 degrees) and explain it using a line through one vertex parallel to the opposite side

Find a missing angle of a triangle from the other two, including the second acute angle of a right triangle (the two acute angles are complementary)

Use the angle sum to decide which angle combinations a triangle can have: at most one right or obtuse angle, and the right angle is the largest angle of a right triangle

Write and solve a linear equation from angle expressions in a triangle, and report the quantity the question asks for

Identify an exterior angle and its two remote interior angles, and apply the exterior angle theorem

Combine triangle angle facts with linear pairs, vertical angles, and parallel-line angle pairs in multi-step figures

SAT Description, and PSAT/NMSQT and PSAT 10 Description: "Know and directly apply relevant theorems such as the: • triangle angle sum theorem." PSAT 8/9 Description (the entire cell): "Know and directly apply the triangle angle sum theorem."