# Triangles Triangles Triangles

Author:
hjelm
Topic:
Triangles

## Overview

In class, we had to determine if squares were actually "squares" or not. We had to drag the vertices to test the squares. I made my own but with triangles. The construction protocol on the right is great to have to have a "step-by-step" building of the triangles.
We know that the only real equilateral triangles are TriangleB, TriangleD and TriangleF. TriangleA is not a triangle because the top releases from the rest of the triangle. Also, TriangleC is not a triangle because we can stretch the triangle in a couple directions. Lastly, TriangleE is not a triangle because the top also releases from the rest of the triangle. This allows students to use what they know about triangles and figure out which ones are true and which ones are false.

## Grade 8

This applies to the grade 8 curriculum Shape and Space (Transformations) specifically number 6. Students have to explain why certain triangles are congruent to an equilateral triangle using the properties. Students are required to: ﻿- Determine the coordinates of the vertices of an image following a given combination oftransformations of the original figure. - Draw the original figure and determine the coordinates of its vertices, given the coordinates ofthe image’s vertices and a description of the transformation (translation, rotation, reflection).

## Grade 9

Also, this applies to the grade 9 Shape and Space (3-D Objects and 2-D Shapes) specifically number 3. Students have to recognize which triangles are similar to an equilateral triangle. Students will have to: ﻿- Determine if the polygons in a given pre-sorted set are similar, and explain the reasoning. - Draw a polygon similar to a given polygon, and explain why the two are similar.- Solve a given problem, using the properties of similar polygons.

## Sample Questions:

Grade 8: Teachers can get students to draw an equilateral triangle using the properties. Then, we can have the students look through the above triangles and see if they are equilateral as well. Grade 9: Teachers will give this to students and have them explain why some of them are similar to an equilateral triangle and some are not similar to an equilateral triangle. Then can then draw two on their own and explain why they are equilateral.

## Conclusion:

I like the way that I can construct all of these triangles before hand and give the program to my students and have them play with it and learn about what an equilateral triangle really is. I would definitely use this in my class because it is easy to use and easy to see which ones are correct and point out and explain which ones are wrong.