Remember all those triangle congruence shortcuts? Well, this is similar to that.

Objective 1a

You will be able to discover and use shortcuts for determining that two triangles are similar

Mr. Labelle helps us review the concept of similar triangles, which requires two key components: congruent angles and proportional sides. The question he leaves us with is, for triangles, must we check both the sides and the angles, or is there a shortcut? Duration_7_09

Objective 1b

This first investigation uses Geogebra to discover if similar triangles can be made from only constructing congruent angles. In doing so, Mr. Labelle reveals some advanced Geogebra techniques that only Canadians know. Duration_9_33

Objective 1c

This video is a conclusion of the previous investigation on Angle-Angle Similarity. Duration_5_06

Objective 1d

As Investigation 1 demonstrated, AA Similarity is a perfectly valid shortcut for showing that two triangles are congruent. Now what about just checking that the sides are proportional? To answer the question, Mr. Labelle turns once again to Geogebra. Duration_9_46

Objective 1e

Here, Mr. Labelle shows us both the SSS and the SAS Similarity Theorems. How our shortcuts are complete. Duration_5_09

Geometry 3(A) describe and perform transformations of figures in a plane using coordinate notation

Geometry 3(C) identify the sequence of transformations that will carry a given pre-image onto an image on and off the coordinate plane

Geometry 4(A) distinguish between undefined terms, definitions, postulates, conjectures, and theorems

Geometry 7(A) apply the definition of similarity in terms of a dilation to identify similar figures and their proportional sides and the congruent corresponding angles

Geometry 7(B) apply the Angle-Angle criterion to verify similar triangles and apply the proportionality of the corresponding sides to solve problems.