EngageNY
Base Angles of Isosceles Triangles
Build confidence in proofs by proving a known property. Pupils explore two approaches to proving base angles of isosceles triangles are congruent: transformations and SAS. They then apply their understanding of the proof to more complex...
Curated OER
Geometry Regents Questions: Isosceles Triangle Theorem
In this isosceles triangle worksheet, students solve 19 multiple choice and short answer problems. Students use the isosceles triangle theorem to determine unknown angle measures.
Curated OER
Isosceles Triangle Theorem
In this geometry worksheet, young scholars differentiate between isosceles and regular triangles. They calculate the area and perimeter of the triangle. There are eleven questions with an answer key.
Curated OER
Isosceles Triangles
Students identify the properties of an isosceles triangle. In this geometry lesson plan, students find the midpoint, median and angle bisector of a triangle. They construct angle bisectors and measure missing angles.
Curated OER
Isosceles Triangles
Learners investigate triangles. In this shapes geometry lesson, students define and state the attributes for equilateral, scalene, and isosceles triangles. Learners locate the prefix "tri" in a variety of words and make connections with...
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...
National Security Agency
Classifying Triangles
Building on young mathematicians' prior knowledge of three-sided shapes, this lesson series explores the defining characteristics of different types of triangles. Starting with a shared reading of the children's book The Greedy...
Virginia Department of Education
Special Right Triangles and Right Triangle Trigonometry
Right triangles are so special! Use special right triangles to discover the trigonometric ratios. Pairs construct special right triangles and find the values of the ratios of the sides. In the process, they discover the ratios stay the...
Curated OER
The Greedy Triangle-Intro to Geometric Shapes
In this geometry lesson, learners read The Greedy Triangle and use geoboards to construct geometric shapes. They identify the number of sides and angles each shape has.
EngageNY
Congruence Criteria for Triangles—ASA and SSS
How do you know if a pair of triangles are congruent? Use the lesson to help class members become comfortable identifying the congruence criteria. They begin with an exploration of ASA and SSS criteria through transformations and...
EngageNY
Triangle Congruency Proofs (part 2)
Looking to challenge your students that have mastered basic triangle congruence proofs? A collection of proofs employ previously learned definitions, theorems, and properties. Pupils draw on their past experiences with proofs to...
Curated OER
Isosceles Triangle Investigation
Students solve problems with isosceles triangles. In this geometry lesson, students identify and use the properties of triangles to solve their problems. They find the median, altitude, and angles to the triangles.
Curated OER
Angle Exploration and Classification
Students compare and contrast angles and identify them as acute, obtuse, right, or straight angles. They create rays and angles using uncooked spaghetti, read and discuss key vocabulary terms, and complete a variety of geometry worksheets.
Curated OER
Angles, Triangles, Quadrilaterals, Circles and Related
Students classify angles. In this angles lesson plan, students explore the characteristics of angles, triangles, quadrilaterals and circles. They identify polygons and sing a classifying angles song. Students participate in a...
Curated OER
Interior Angles of Regular Polygons
High schoolers investigate the interior angles of a triangle. In this geometry lesson, students create the formula to calculate the angles inside a triangle. They observe the total sum of a triangles angle on the navigator.
EngageNY
Using Trigonometry to Determine Area
What do you do when you don't think you have enough information? You look for another way to do the problem! Pupils combine what they know about finding the area of a triangle and trigonometry to determine triangle area when they don't...
Curated OER
The Sum of All Angles
Students add up the different angles using the angle addition postulate. In this geometry lesson, students differentiate between interior and exterior angles. They calculate the different angles for triangles and use proof to show their...
Curated OER
Review of Triangles
Students investigate the Pythagorean Theorem. In this geometry activity, students define angles and sides of right triangles. They calculate the area and surface area using formulas derived by the Pythagorean Theorem.
Curated OER
Triangle Classification
Students classify different types of triangles. In this geometry instructional activity, students identify and use properties of triangles. They differentiate between isosceles and equilateral triangles.
Curated OER
ARE YOU A TRIANGULATEER?
Students explore about triangles and their relationship to the worlld around them. They are able to identify triangular shapes in their environment. Students are able to communicate to one another their understanding of triangles outside...
Alabama Learning Exchange
Trapezoids: What's Equal or Right About Them?
Pupils explore the concept of trapezoids. In this trapezoids instructional activity, students identify legs and bases of a trapezoid. Pupils discuss the similarities and differences between isosceles trapezoids and right...
Curated OER
Designing a Quilt Pattern
Learners create and color a one-patch quilt design based upon a regular hexagon. They examine quilts and photos of quilt designs, read a handout, and complete their quilt design on a worksheet.
Curated OER
An Introduction to Quadrilaterals
Students explore different types of quadrilaterals. Students define the terminology used with quadrilaterals. They create particular quadrilaterals based on specific characteristics of the quadrilaterals using an online tool.
Curated OER
Polygons All Around Us!
Pupils 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. Pupils identify different geometric shapes in the...