Interactive
National Council of Teachers of Mathematics

Scale Factor

For Students 6th - 12th Standards
Does doubling mean everything doubles? Learners adjust the scale factor between two rectangles. Using the calculated measurements, pupils investigate the ratios between the lengths, perimeters, and areas of the rectangles.
Interactive
Curated OER

Similar Figures

For Students 7th - 10th
In this similar figures learning exercise, students identify the meaning of similar, corresponding sides, and congruent.  They use proportions to find the length of a missing side.  Students dilate given figures according to a...