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Kala - Relationship: Exterior & Interior Angles

Explore the relationship between the sum of the two remote interior angles and the exterior angle of the third angle in a triangle by dragging sliders and making observations.
Drag the two sliders to transform the angle measures for angle A and B of the triangle. Compare the sum of these angles to the exterior angle at C in the triangle. Is this true for any triangle ABC? 1. What is the sum of the interior and exterior angles formed at point C in the triangle? 2. Create an acute triangle by dragging vertex A to the right. What is the sum of angle A and B? What is the measure of the exterior angle at point C? 3. Create an obtuse triangle. What is the sum of angle A and B? What is the measure of the exterior angle at point C? 4. What do you notice about the relationship between the two remote interior angles of a triangle and the exterior angle of the third angle of a triangle? Turn on the check box "show relationship" to check your statement.