Lesson Plan
Illustrative Mathematics

Two Wheels and a Belt

For Teachers 9th - 10th Standards
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...
Activity
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Illustrative Mathematics

Midpoints of the Sides of a Paralellogram

For Teachers 9th - 12th Standards
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...
Lesson Plan
Shodor Education Foundation

Triangle Area

For Teachers 6th - 9th Standards
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...
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Curated OER

Inscribing a Hexagon in a Circle

For Teachers 9th - 11th Standards
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...
Activity
BBC

Bbc: Angles

For Students 6th - 9th Standards
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.
Activity
Texas Instruments

Texas Instruments: Properties of Reflections

For Teachers 9th - 10th
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...
Activity
CK-12 Foundation

Ck 12: Angles Outside a Circle

For Students 9th - 10th
[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.
Activity
Texas Instruments

Texas Instruments: Geometric Representation of Trig Functions

For Teachers 9th - 10th Standards
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...