Illustrative Mathematics
Two Wheels and a Belt
Geometry gets an engineering treatment in an exercise involving a belt wrapped around two wheels of different dimensions. Along with the wheels, this belt problem connects concepts of right triangles, tangent lines, arc length, and...
Illustrative Mathematics
Midpoints of the Sides of a Paralellogram
This task asks learners to prove that the segment joining the midpoints of two sides of a parallelogram is both congruent and parallel to an adjacent side of the parallelogram. The activity would be good to use in a discussion about how...
Shodor Education Foundation
Triangle Area
While the lesson focuses on right triangles, this activity offers a great way to practice the area of all triangles through an interactive webpage. The activity begins with the class taking a square paper and cutting in in half; can they...
Curated OER
Inscribing a Hexagon in a Circle
This activity is a follow-on activity to inscribing a square in a circle. The overall problem is more complex. It deals with geometric constructions, properties of triangles, and regular hexagons. The final part of the activity...
BBC
Bbc: Angles
You can pick up some valuable pointers on angles and lines here. When you finish working your way through the pages you can take an on-line "Test Bite," and check your understanding.
Texas Instruments
Texas Instruments: Properties of Reflections
I use this activity in the beginning of the school year when introducing terminology such as angles, lines, segments, measures, perpendicular etc. The original material is from the SIMMS Integrated Mathematics using Technology, I have...
CK-12 Foundation
Ck 12: Angles Outside a Circle
[Free Registration/Login Required] Students will move the points on the line segments to explore anlge measures outside the circle. Click learn more to watch a video and click challenge me to answer a practice question.
Texas Instruments
Texas Instruments: Geometric Representation of Trig Functions
Using similar triangles, a relationship is established between the six trigonometric functions of an angle and simple line segments. These relationships are then confirmed using line segment measurement capabilities of the graphing...