Google Classroom
GeoGebraGeoGebra Classroom

How Many Pieces?

Below is triangle ABC. Your task is to create a similar triangle to triangle ABC. The purpose of the activities below is to determine what is the least amount of information you can use to construct a triangle that will be similar to the original triangle ABC. Once you have moved the sliders to fit the given criteria, try and move other parts of the triangle. After everyone has had a chance to make a triangle with the given criteria, we'll compare and calculate to see if the given information was enough to make everyone's triangles the similar to triangle ABC.
Attempt #1...one angle For this first drawing lets make just one angle measure congruent to the original triangle ABC. Draw triangle DEF with the given measures: angle DEF = 82 degrees Move the green slider so that angle DEF is 82 degrees. Is the triangle you constructed similar to the original triangle ABC?
Attempt #2...two angles For second drawing lets make two angle measures congruent to the original triangle ABC. Draw triangle DEF with the given measures: angle DEF = 82 degrees angle ACB = 38 degrees Move the green slider so that angle DEF is 82 degrees and move the purple slider so that angle ABC is 38 degrees. Is the triangle you constructed similar to the original triangle ABC?
Angle-Angle Triangle Similarity Theorem: In two triangles, if two pairs of corresponding angles are congruent, then the triangles must be similar. (Theorem)