How this resource helps
General proofs use established angle, congruence, and dilation facts. A parallel through a vertex proves angle sum; subtraction proves the exterior-angle theorem; SAS proves base-angle equality; a half-scale dilation proves midsegment parallelism and half-length. These results justify relationships in larger figures. Standard NC.M2.G-CO.10: Prove theorems about triangles and use them to prove relationships in geometric figures including: The sum of the measures of the interior angles of a triangle is 180º. An exterior angle of a triangle is equal to the sum of its remote interior angles. The base angles of an isosceles triangle are congruent. The segment joining the midpoints of two sides of a triangle is parallel to the third side and half the length.
What’s Included
- One editable 16:9 PowerPoint with 35 slides and teacher speaker notes on every slide.
- Full standard and all its subparts, unpacking, essential question, learning goals, warm-up, vocabulary and teaching routine.
- Five worked models, guided practice, partner work, five scored independent items, small-group intervention and an open extension.
- Matched blank/completed guided notes, a three-item exit ticket and reflection.
- Editable mathematical diagrams, tables and graphs where relevant. Graphing calculator or spreadsheet activities are included where required by the standard.
Resource details
- Grade / course
- NC Math 2
- Subject and resource type
- Mathematics · PowerPoint Lesson
- Files
- 0 main PDF pages · 35 editable slides · PPTX
- Estimated completion time
- 45–60 minute lesson
- Answer key
- Teacher answer guidance is included in the speaker notes on every slide.
Standard or objective
NC.M2.G-CO.10 — Prove theorems about triangles and use them to prove relationships in geometric figures including: The sum of the measures of the interior angles of a triangle is 180º. An exterior angle of a triangle is equal to the sum of its remote interior angles. The base angles of an isosceles triangle are congruent. The segment joining the midpoints of two sides of a triangle is parallel to the third side and half the length.
Prove theorems about triangles and use them to prove relationships in geometric figures including: The sum of the measures of the interior angles of a triangle is 180º. An exterior angle of a triangle
Original Saint Pierre Learning Resources lesson aligned to the North Carolina Standard Course of Study for NC Math 2 Mathematics.
Learner directions
Students work through each slide as the teacher directs, completing practice and exit-ticket items.
Teaching suggestions
Project each slide in order. Follow the teacher models, then guide practice as labeled on each slide.