Lesson Plan
Curated OER

Geometry Journal: Isosceles Triangles

For Teachers 10th - 12th
In this isosceles triangles worksheet, students justify and determine the symmetry of an isosceles triangle. They explore the bisector of rectangles. This three-page worksheet contains two problems. Answers are listed on page three.
Lesson Plan
Illustrative Mathematics

Lines of Symmetry for Triangles

For Teachers 3rd - 5th Standards
What can symmetry tell us about triangles? After looking at four examples, learners will come to realize that lines of symmetry are different for equilateral, isosceles, and scalene triangles. Use this guided practice activity as an...
Lesson Plan
Curated OER

Triangles

For Teachers 5th - 6th
In this math worksheet, students answer 3 questions about an equilateral triangle. Students then answer 3 questions about isosceles triangles. Students then calculate missing angles on isosceles triangles.
Lesson Plan
Curated OER

Toothpick Triangles

For Teachers 4th - 8th
Learners draw a chart (included in the lesson) to use with their investigation. They review terminology of triangles and receive toothpicks to use in the lesson. Beginning with three toothpicks, students form a triangle. They complete...
Lesson Plan
Curated OER

Study Buddies: Classifying Triangles

For Teachers 4th - 5th
In this math worksheet, students analyze an informative chart about the measurement and angles of equilateral, isosceles and scalene triangles. Students then answer 5 questions about classifying triangles.
Lesson Plan
Alabama Learning Exchange

What You Know About the Bermuda Triangle?

For Teachers 9th - 12th Standards
Get lost in the classifications. Using the backdrop of the Bermuda Triangle, pupils classify it by angle and side measures. They also learn information about the triangle and its history.
Lesson Plan
Curated OER

Geometry of Triangles - Week 6

For Teachers 10th - 12th
In this triangle worksheet, students explore the characteristics of triangles. They find the area of a pentagon, lengths of the sides of a triangle and the area of a quadrilateral. This two-page worksheet contains seven problems.
Lesson Plan
Curated OER

Geometric Figures-Triangles

For Teachers 4th
Fourth graders explore triangles. For this math lesson, 4th graders discuss the different types of triangles. Students create triangles using wiki sticks. Students complete an online matching game.
Lesson Plan
Curated OER

Geometric Properties

For Teachers 9th - 12th
Young scholars find triangular angles using the angle theorem. In this geometry lesson, students describe labeled triangles, use the pythagorean theorem, and rewrite information about triangles in standard form.
Lesson Plan
Curated OER

Isosceles Triangles

For Teachers K - 2nd
Students investigate triangles. In this shapes geometry lesson, students define and state the attributes for equilateral, scalene, and isosceles triangles. Students locate the prefix "tri" in a variety of words and make connections with...
Lesson Plan
Virginia Department of Education

How Many Triangles?

For Teachers 9th - 11th Standards
Something for young mathematicians to remember: the sum of any two sides must be greater than the third. Class members investigates the Triangle Inequality Theorem to find the relationship between the sides of a triangle. At the...
Lesson Plan
Texas Instruments

Identifying a Triangle by its Sides and Angles

For Teachers 9th - 12th Standards
Identify triangles by their angle measures and side lengths by looking at and measuring angle measures and side lengths. Use Cabri Jr. to construct various triangles, then manipulate the construction to create the 6 types of triangles,...
Lesson Plan
Curated OER

Constructions Triangles

For Teachers 10th Standards
Learners explore the difference between a construction and a drawing. They focus on various ways to construct different types of triangles. The activity is an application of Cabri Jr. and reinforces the difference between a constructions...
Lesson Plan
Willow Tree

Angle Sum Property of Triangles

For Students 8th - 11th Standards
All triangles have some things in common. Using these properties of triangles, learners find missing angle measures. Scholars use the Angle Sum Property and properties of special triangles throughout the lesson.
Lesson Plan
National Security Agency

Classifying Triangles

For Teachers 4th - 8th Standards
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...
Lesson Plan
Curated OER

Varieties of Quadrilaterals

For Teachers 4th - 7th
Learners classify quadrilaterals, In this quadrilaterals lesson, students watch a video about parallelograms, discuss the different types of quadrilaterals, and complete a worksheet classifying quadrilaterals.
Lesson Plan
Curated OER

Types of Triangles

For Teachers 1st - 2nd
Young scholars classify triangles by the length of their sides. In this geometry lesson, students use a white board to demonstrate the angles of various triangles. Young scholars construct an equilateral, isosceles, and a scalene triangle.
Lesson Plan
Curated OER

Identify triangles

For Teachers 9th - 10th
Students explore triangles. In this geometry lesson, students will create note cards with pictorial depictions of right, acute,obtuse, scalene, isosceles, equilateral and equiangular triangles. Students will verbally describe each type...
Lesson Plan
Curated OER

Identifying Triangles

For Teachers 6th
Sixth graders identify and define a variety of triangles. In this identification of triangles lesson, 6th graders draw examples of each triangle on a whiteboard, then complete a worksheet.
Lesson Plan
Curated OER

Exploring Triangles

For Teachers 1st - 12th
Students research the different types of triangles, including right, isosceles, scalene, and equilateral triangles. They identify the characteristics of various types of triangles and then draw them using appropriate vocabulary to...
Lesson Plan
Curated OER

Acute Triangles

For Teachers 4th - 8th
Learners study acute triangles. They measure angles using a protractor, then classify the triangles as either right, obtuse, or acute. Everyone creates a design for a Navajo rug using only acute triangles.
Lesson Plan
Curated OER

Triangles

For Teachers 5th - 6th
Students discover the difference between triangles. For this triangle lesson plan, students discuss the different types of triangles, then draw the three different types of triangles. The teacher will draw, or model, how to draw the...
Lesson Plan
Curated OER

Triangles

For Teachers 5th - 6th
Learners draw triangles. In this shapes lesson, students discuss what they already know about triangles, what they are and what they are made up of. Learners discuss the types of triangles and practice drawing each type.
Lesson Plan
Curated OER

Geometry of Triangles - Week 6

For Teachers 12th - Higher Ed
In this geometry of triangles worksheet, students find the length of sides, are, and angle measurement of inscribed triangles, pentagons, and midpoint of a line. This two-page worksheet contains seven problems.