US Common Core State Standard Math HSG-CO.C.10
Demonstrations 1 - 15 of 15

Description of Standard: Prove theorems about triangles. Theorems include: measures of interior angles of a triangle sum to 180°; 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.

 Halving a Triangle Angle and Length Measurement of a Polygon The Interior Angles of a Triangle Sum to Pi The Medians of a Triangle Divide It into Three Smaller Triangles of Equal Area The Medians of a Triangle Are Concurrent: A Visual Proof The Centroid of a Triangle Divides Each Median in the Ratio 1:2 Euclid, Book 3, Proposition 22 The Sum of the Interior Angles of a Triangle Equals 180 Degrees by Paper Folding Interior Angles of a Triangle Medial Division of Triangles The Erdös-Mordell Inequality Angles in a Quadrilateral Total 360° Angles in a Triangle Total 180 Degrees Oriented Triangle Angles The Triangle Inequality

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