G.CO.10

Prove theorems about triangles. Theorems include: measures of interior angles of a triangle sum to 180 degrees; base angles of isosceles triangles are congruent; the segment joining midpoints of two sides of a triangle is parallel to the third side and half the length; the medians of a triangle meet at a point.

1. Shape Up! 11 - calculate angle size, angle sum of a triangle
2. Shape Up! 10 - calculate angle size, supplementary angels, angle sum of a triangle
3. Shape Up! 9 - angle sum of a triangle, exterior angles, revolution
4. Shape Up! 3 - identify equal angles
5. Shape Up! 1 - exterior angles of a triangle
6. ABCs 1 - triangle geometry, equal angles opposite equal sides