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...
Texas Instruments
Identifying a Triangle by its Sides and Angles
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,...
Illustrative Mathematics
Lines of Symmetry for Triangles
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...
Curated OER
Triangle Puzzler
In this math worksheet, students analyze a chart and identify the names of 9 types of triangles. Students also find as many kinds of triangles they can in a given figure.
Curated OER
Geometric Figures-Triangles
Fourth graders explore triangles. In this math lesson plan, 4th graders discuss the different types of triangles. Students create triangles using wiki sticks. Students complete an online matching game.
Curated OER
Symmetries of a Quadrilateral I
Learners examine the properties of quadrilaterals from the point of view of rigid motion. Different types of quadrilaterals are characterized by their symmetries, so learners explore the symmetries of a described quadrilateral to...
Curated OER
Exploring Triangles
Learners 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...
Alabama Learning Exchange
Triangle Congruence with Rigid Motion
Combine transformations and triangle congruence in a single lesson. Scholars learn to view congruent triangles as a rigid transformation. Using triangle congruence criteria, learners identify congruent triangles and the rigid...
Curated OER
SuperShapes, Part 1; "Tri"ing Triangles
An outstanding lesson on triangles awaits your math scholars. Learners focus on the triangle, which is the strongest of all polygons. They see the role that triangles play in the design of buildings, and learn about triangle...
Curated OER
Types of Sentences
Fourth graders identify and write different types of sentences. In this sentences lesson plan, 4th graders use pictures and animation to write declarative, interrogative, imperative, and exclamatory sentences.
Curated OER
Classifying Triangles by the Length of the Sides Using Cabri Jr.
Learners follow detailed directions to create triangles on their graphing calculator. In this properties of triangles instructional activity, they will create triangles on their calculators using the Cabri Jr. application. They then...
Curated OER
Drawing a Triangle with Cabri Junior
Learners draw triangles on their graphing calculators using the Cabri Junior application. In this graphing calculator lesson, students follow step by step directions to create triangles on their calculator. They identify the type of...
Curated OER
Types of Triangles
Students classify triangles by the length of their sides. In this geometry lesson, students use a white board to demonstrate the angles of various triangles. Students construct an equilateral, isosceles, and a scalene triangle.
Curated OER
Exterior and Interior Angles of Triangles
Tenth graders explore the exterior and interior angles of triangles. They use a theorem in order to prove a theorem about all polygons. Students use the theorem and its applications to find the angles of different types of triangles.
Curated OER
Types of Triangles
Fifth graders explore the required functions of the Geometer's Sketchpad. Using the computer software, they construct similar triangles and identify them by angles and sides. Students classify triangles. Afterward, they complete problems...
Curated OER
8th Grade Math Classifying Triangles and Quadrilaterals
Eighth graders engage in a lesson that is about classifying polygons with the focus being upon specific triangles and quadrilaterals. They conduct activities using cutouts for kinesthetic learners to help make connections while...
EngageNY
Applying the Laws of Sines and Cosines
Breaking the law in math doesn't get you jail time, but it does get you a wrong answer! After developing the Law of Sines and Cosines in lesson 33 of 36, the resource asks learners to apply the laws to different situations. Pupils must...
Curated OER
Congruent Triangles
Students identify properties of triangles. In this geometry activity, students differentiate between similar and congruent triangles. They use the umber of sides to help define the angle of the polygon.
Curated OER
Basic Right Triangles
Elementary schoolers examine the attributes of triangles. In this triangle lesson, learners compare regular triangles and right triangles. They explore vertices and angles and investigate obtuse and acute angles. Pupils draw multiple...
Curated OER
The Truth About Triangles And Proofs
High schoolers engage in a lesson 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...
Curated OER
Shapes and Tools
Young learners view different shapes drawn by the teacher on the board. The teacher identifies each shape by name and discusses the importance of knowing the difference between shapes when building something. The pupils complete the...
Curated OER
Scalene Triangles
Fifth graders identify and classify scalene, equilateral, and isosceles triangles. In this triangle lesson, 5th graders define the different attributes of 3 types of triangles and sort them by descriptions and...
Curated OER
Pascal's Triangle
Students explore the concept of Pascal's Triangle. In this Pascal's Triangle lesson plan, students use an applet called 'Coloring Multiples' to explore Pascal's Triangle. Students develop patterns starting with various numbers in...
Curated OER
Identify triangles
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...