Exterior Angle of a Triangle
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Can you figure out a way to determine the measure of angle BCD in each sketch above without using a measuring device or Sketchpad’s tools? Study your results carefully. Use the Sketchpad file (exterior.gsp) to help you. Next determine angle BCD in the figures above without using any mearement device like a protractor. Explain (1) what you did and (2) why it works.




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