Interactive
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GeoGebra

Conjectures and Proof

For Students 9th - 12th Standards
Transform proofs using triangle rotations. By rotating a triangle around various points, class members develop proofs. Participants prove relationships of alternative interior angles formed by parallel lines and the sum of the interior...
Interactive
Curated OER

Similar Polygons

For Students 7th - 8th
In this similar polygons activity, students identify the corresponding sides of polygons.  They use proportions to solve problems.  Students determine the scale factor of similar figures.  This two-page activity contains...