Khan Academy
Khan Academy: Challenge Problems: Inscribed Angles
Solve two challenging problems that apply the inscribed angle theorem to find an arc measure or an arc length.
Doina Popovici
Math Play: Classifying Angles Jeopardy Game
An online Jeopardy game where students describe the type of angles, measurement of angles, and identify whether angles are complementary, supplementary or congruent.
Illustrative Mathematics
Illustrative Mathematics: F Tf.1 What Exactly Is a Radian?
For this task, young scholars use a piece of string or another tool to measure the radius of the circle and then mark off the corresponding arc length on the unit circle as many times as they need to for 0, 1, 2, 3, 4, 5, and 6 radians....
Science and Mathematics Initiative for Learning Enhancement (SMILE)
Smile: Similarity
This site contains a lesson plan for high school age students. The objective is to discover the factor of proportionality in similar polygons and to relate this factor to the perimeters and areas of similar polygons.