Assignment Six
Question #2

The purpose of this assignement is to explore the medians triangles of equilateral, isosceles, and right triangles.

 

This figure is an equilateral triangle as can be seen by the congruent sides. The medians are represented in colors of red, green, and blue.

If we remove the medians and construct a triangle from the medians, will the new triangle be equilateral?

 

 

As we can see by the congruent side measures, the new triangle of medians is also an equilateral triangle. Will this always be true? Moving the original triangle so the measures of sides and medians change, we can record the measures on a table. As can be seen, the chart indictes that the medians of an equilateral triangle are equal and would therefore generate an equilateral medians triangle. (This does not constitute a proof of deductive reasoning, but is useful for students to see concretely the beginnings of such thought.)

 

If we our original triangle is isosceles, will the triangle of medians also be an isosceles triangle?

As can be seen by the side measures, this triangle is isosceles. The medians are represented in colors of red, green, and blue. If the medians are removed and a new triangle is constructed, the new triangle of medians is also isosceles.

Will the triangle of medians of and isosceles triangle always be isosceles? We can use thefollowing table of measures and inductive reasoning that it is likely so.

Will a right triangle of medians always generate a right triangle of medians? The following triangle is a right triangle as can be see by the measure of angle B.

 

When the medians are removed to form another triangle, it does not necessarily follow that it will be a right triangle, as can be seen below.

 


 

By using parallel lines, we can construct the median triangle whose changes coinside with the original triangles as it is manipulated. The following construction illustrates both the original triangle and the median triangle as right triangles.

 
 
 

At this point in the investigation, I would ask my students to manipulate the triangle and use the tabulation to explore the ratios of the side measures to determine under what conditions will the original triangle and median triangle both be right triangle. Click here to manipulate.


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