Curated OER
Light Bounce
Students solve problems involving triangles. In this geometry instructional activity, students apply properties of triangles to find the missing angles and sides. They identify angles of parallel lines cut by a transversal.
Curated OER
Angle Action 1,2 and 3
Students investigate angles through construction. In this geometry lesson, students use a protractor to identify the measurement of an angle. They identify angles cut by a transversal and two parallel lines.
Curated OER
Perpendicular Lines
Learners differentiate between parallel and perpendicular lines. In this geometry lesson, students identify the different angles created by perpendicular lines and parallel lines. They name the angles that are form when parallel lines...
Mt. San Antonio Collage
The Trapezoid
Enjoy this nicely organized activity that puts together multiple problems regarding trapezoid proofs. The resource can be used as a guide that begins with proving properties and ends with solving for measures of line segments.
Mathematics Assessment Project
Identifying Similar Triangles
Math whizzes work with angle sums and exterior angles to figure out the measure of other angles. This particular publication provides comprehensive support in the form of an anticipatory activity, questions designed to prompt discussion,...
EngageNY
Unknown Angle Proofs—Proofs with Constructions
Provide your emerging mathematicians with the tools to learn as they incorporate auxiliary lines to solve unknown angle proofs in this continuing segment. They decipher information from a diagram to uncover the missing pieces and...
EngageNY
Similarity and the Angle Bisector Theorem
Identifying and verifying reproducible patterns in mathematics is an essential skill. Mathematicians identify the relationship of sides when an angle is bisected in a triangle. Once the pupils determine the relationship, they prove it to...
EngageNY
Congruence Criteria for Triangles—SAS
Looking for a different approach to triangle congruence criteria? Employ transformations to determine congruent triangles. Learners list the transformations required to map one triangle to the next. They learn to identify congruence if...
EngageNY
Informal Proof of AA Criterion for Similarity
What does it take to show two triangles are similar? The 11th segment in a series of 16 introduces the AA Criterion for Similarity. A discussion provides an informal proof of the theorem. Exercises and problems require scholars to apply...
EngageNY
More About Similar Triangles
Determine whether two triangles are similar. The lesson presents opportunities for pupils to find the criterion needed to show that two triangles are similar. Scholars use the definition of similarity to find any missing side...
Curated OER
Strongest Polygon
Learners define and identify shapes by name. In this geometry lesson plan, students construct, identify and compare polygons based on the number of sides. They classify each shape based on their angle sum theorem.
Curated OER
Incredible Edible Bridges
Students create a bridge using engineering and geometric concepts. In this geometry lesson, students identify the missing measures of polygons sides and angles. They work together to solve real life situation using problem solving skills.
Curated OER
Logical Relationship of Postulates & Theorems
In this postulates and theorems worksheet, students explore a concept map containing information about angles and sides, alternate interior angles, and diagonals of a parallelogram. They use the concept map to prove theorems dealing...
Curated OER
Constructing Midsegments of Triangles
Learners construct midsegments. In this geometry instructional activity, students make conjectures and apply properties of triangles to solve problems. They complete an activity on the computer.