Students will use Cabri Jr. to discover two properties of similar triangles: corresponding angles are congruent and corresponding sides are proportional.
Before the Activity
The file SIMTRI needs to be sent to the students calculators. Students will need to have a little knowledge of the graphing calculator. Steps are given, but not detailed enough for a beginner.
During the Activity
The attached document includes step by step instructions for the students to complete the discovery activity. Assistance by be need with the Cabri Jr. application. Instruct students to record all the data from the measurements in the table first, then quit out of the application to do the calculations if needed.
After the Activity
The similarity ratio for the first table is 2:1 and the second similarity ratio is 1:2. Have select students record step 5 on an overhead transparency to be shared with the class to ascertain the class has the correct understanding of the properties of similar polygons.