Curated OER
Triangle Congruence
In this triangle congruence instructional activity, students review 4 triangle congruence properties and 4 examples. Students are then prompted to complete 15 problems analyzing whether two triangles are congruent and determine by which...
Curated OER
Mathematical Wackie Wordies
In this word worksheet, 9th graders examine pictures and write a mathematical phrase to describe the picture. This one-page worksheet contains 25 problems. Answers are provided.
Curated OER
Understanding Fundamental Trigonometric Identities
Students are introduced to the basic trigonometric identities. Using a diagram, they discover why the parts of the unit circle as named as they are and use equations to finalize the Pythagorean trigonometric identities. They also review...
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...
Curated OER
The Truth About Triangles And Proofs
Students engage in a lesson plan that is about the classification of triangles and the mathematical proofs involved in working with them. They work on a variety of problems that are created by the teacher with the focus upon the...
Alabama Learning Exchange
Creating a Reflection
Investigate geometric reflections in this geometry lesson. Create geometric reflections that show the reflection across the x and y axis of a coordinate graph. Learners watch a teacher demonstration before proceeding on their own. They...
Curated OER
Polygons All Around Us!
Students explore the concept of polygon properties. In this polygon properties lesson, students draw polygons with different numbers of sides such as pentagons, octagons, hexagons, etc. Students identify different geometric shapes in the...
Curated OER
Similar Triangles
Ninth graders find the height of every day objects using techniques learned through postulates that allow triangles in a problem to be similar. They calculate the length of a missing side and solve proportions.
Curated OER
Why can't We Use SSA to Prove Triangles Congruent?
Students investigate triangles and congruences. In this geometry lesson, students differentiate between inductive and deductive reasoning. They differentiate between similar and congruent triangles.