1. Measure each of the interior angles of your triangle (ÐABC, ÐBCA, ÐCAB). Measure each of the exterior angles of your triangle (ÐBAD, ÐCBE, ÐFCA)
2. Change the values for the angles by dragging some of the points around, and record the new values. Repeat for several different triangles and record the values for three (3) of them.
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Interior Angles |
Exterior Angles |
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| Triangle |
ÐABC |
ÐBCA |
ÐCAB |
ÐBAD |
ÐCBE |
ÐFCA |
| 1 |
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| 2 |
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| 3 |
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3. Write the algebraic relationship that connects the measures of the exterior angles of a triangle.
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4. In the triangles that you have drawn, the exterior angle ÐBAD has the interior angles ÐBCA and ÐABC opposite to it (i.e. across from it). What are:
a) the interior angles opposite ÐCBE: _______________
b) the interior angles opposite ÐFCA: _______________
5. Using the information from your table in question 3, complete the following table
| |
Exterior Angle |
Opposite Interior
Angles |
|
| Triangle |
ÐBAD |
ÐBCA |
ÐABC |
| 1 |
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| 2 |
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| 3 |
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6.
Write the algebraic relationship that shows how the measure of an exterior
angle is related to the angles inside the triangle opposite to it.