Lessons with iGeom
Introduction to iGeom and interactive geometry
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The next exercises are used to introduce the 4 most famous Notable Points: barycenter (centroid), circumcenter, incenter and the orthocenter.
Here you are challenged to construct some aditional measures in order to observe special properties related to these points.
You must attempt to the exercise requirements, since the automatic evaluation of iGeom uses an answer model. This means that, when the model requires a segment (p.e., in the first one) the evaluation algorithm of iGeom will mark as "not correct" a construction using a line or a ray.

 Exercises  Subjects
Exercise 1 Given the triangle ABC, build its barycenter (centroid), represented by the point P. Construct the interactive areas for APB, BPC and CPA, using these specific order.
Use segment to construct P, do not use line or ray.
Exercise 2 Given the triangle ABC, build its circumcenter, represented by the point P. Construct the interactive distances |P-A|, |P-B| and |P-C|.
The answer must be: the circumcenter P (point) and the 3 distances.
Exercise 3 Given the triangle ABC, construct its incenter, represented by the point P. Construct the interactive distances d(P,AB), d(P,BC) and d(P,AC) (representing the distance of P to each line).
The answer must be: the incenter P (point) and the 3 distances.
Exercise 4 Given the triangle ABC, construct its orthocenter P and the distances d(A,P), d(P,BC), d(C,P) and d(P,AB). Construct the interactive expression d(C,P)*d(P,AB) and d(A,P)*d(P,BC).
The answer is: the orthocenter point P and the 2 expressions d(C,P)*d(P,AB) and d(A,P)*d(P,BC).

Remember:

  1. iGeom do not use the "drag-and-drop" pattern, in order to reduce stress-related muscle tension, reducing harm with the intensive use of the software. So, usually you need to click the construction button, them click the drawing area (or some object).
  2. After you finish you exercise answer, please, click the button
  3. Next















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