i can use theorems, postulates and/or definitions to prove theorems about triangles including:...
TRANSCRIPT
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Angles of Triangles
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Essential Question: How does the angle sum theorem help you find the measures of missing angles in triangles?
I can use theorems, postulates and/or definitions to prove theorems about triangles including: measures of interior angles of a triangle sum to 180 degrees
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Triangle Angle Sum Theorem
The sum of the measures of
the angles of a triangle is 180
degrees
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Let’s try to understand why this is true.
Let’s prove it. First Draw this picture, then write the proof below
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The Triangle Angle Sum Theorem also leads us to another observation……
If I know two of the angles in a triangle, to find the third angle I….
CAN SET THE SUM OF THE THREE ANGLES EQUAL TO 180 AND SOLVE FOR THE THIRD ANGLE
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Using the Triangle Angle Sum Theorem….
This is just an example…NOT the example from your notes…..
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Triangle Exterior Angle Theorem
The measures of each exterior
angle of a triangle equals the sum of it’s
two remote (non-adjacent) interior
angles.
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Now let’s try to understand why this is true. Let’s prove it. First draw this picture, then write the proof.