2015 UM2TO Math-a-thon Problems. Good Task on Angle Measures. Illustrative Mathematics. CCSS Sample Math Tasks (Illinois) Dan Meyer's Three-Act Math Tasks. Math Problems of Varying Difficulty. Solutions to "Problems of Varying Difficulty" NCTM Brain Teasers. Sliding Triangle The triangle at left lies on a flat surface and is pushed at the top vertex.
The length of the congruent sides does not change, but the angle between the two congruent sides will increase, and the base will stretch. Math Tasks from LTC 4571 (Methods 1) Volume Experiment. Opus: Free, Common Core Math.