CCSS HSG-CO.C.10 Worksheets
Geometry · Congruence
Prove triangle theorems, including the 180-degree interior-angle sum, congruent base angles in an isosceles triangle, the triangle midsegment result, and concurrence of the medians.
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Deliver a whole lesson on HSG-CO.C.10 from a textbook-grade teaching unit, with a hook, worked examples, diagrams, misconceptions, and an exit ticket.
Teaching guide
Prove triangle theorems, including the 180-degree interior-angle sum, congruent base angles in an isosceles triangle, the triangle midsegment result, and concurrence of the medians.
| Statement | Reason |
|---|---|
| 1. is a triangle. | Given |
| 2.Draw line n through Q, parallel to line RP. | Construction (Parallel Postulate) |
| 3. and ( and are the angles n makes with QR and QP, on either side of ). | Alternate Interior Angles Theorem |
| 4. = and = . | Definition of congruent angles |
| 5. + + = 180°. | Angles on a straight line sum to 180° |
| 6. + + = 180°. | Substitution Property of Equality |
| 7. + + = 180°. | Commutative Property of Addition |
Generated and checked in code, so it is correct.