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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.
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Worksheet
Curated OER

Geometry - Angles Overview

For Students 7th - 8th
Learners address 14 questions that include naming all pairs of opposite and supplementary angles for sets of intersecting lines and then, finding the measure of the unknown angle. They determine the measure of the angle that is...
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Worksheet
Curated OER

To Be a Triangle Or Not To Be a Triangle?

For Students 10th
In this triangles worksheet, 10th graders solve and complete 10 different problems that include applying the Triangle Inequality Theorem. First, they use the illustrated triangles and the data table to test the theorem. Then, students...
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Worksheet
Curated OER

Angles Activities

For Students 5th - 8th
A series of geometry worksheets have mathematicians constructing, dissecting, overlapping, and measuring as they analyze angles in various contexts. Learners use symmetry and reflections in a compass rose to write instructions on...
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Interactive
Curated OER

Angles in a Triangle

For Students 10th
In this geometry learning exercise, 10th graders determine the measure or measures of the missing angle(s) in a triangle. The one page interactive learning exercise contains four questions. Answers and hints are included. 
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Workbook
1
1
University of Utah

Geometry: Angles, Triangles, and Distance

For Students 8th Standards
The Pythagorean Theorem is a staple of middle school geometry. Scholars first investigate angle relationships, both in triangles and in parallel lines with a transversal, before proving and applying the Pythagorean Theorem.
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Lesson Plan
Curated OER

Exploring Characteristics of Triangles

For Teachers 9th - 11th
Students draw triangles and explore the classification of each using the measures of interior angles and lengths of sides. They investigate the sum of the interior angles of various triangles and conjecture and prove the theorem: The...
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Worksheet
Curated OER

Section 2.5 - Problem Solving (Part B)

For Students 7th - 12th
Trying to figure out the perimeter of a geometric figure? Here are a few word problems to set up algebraic equations to solve for perimeter. There are also some word problems to set up algebraic equations to solve for angles in a...
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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 Triangle,...
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Assessment9:45
Mathed Up!

Angles in Polygons

For Students 8th - 10th Standards
Show your class that finding angle measures is a regular calculation with a resource that provides 12 problems dealing with the measures of angles in regular polygons. Pupils use formulas for the sum of measures of angles in a polygon to...
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Interactive
Shodor Education Foundation

Squaring the Triangle

For Students 8th - 12th Standards
Teach budding mathematicians how to square a triangle with an interactive that shows a graphical proof of the Pythagorean Theorem. Pupils alter the lengths of the legs using sliders. Using the inputted lengths, the applet displays the...
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Worksheet
Curated OER

Measuring Angles in Triangles

For Students 10th
In this measuring angles in triangles activity, 10th graders solve 12 different measurement problems with angles within triangles. First, they find the value of x in each triangle given the angle measurements. Then, students find the...
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Lesson Plan
Curated OER

Triangle Sum Theorem

For Teachers 9th - 12th Standards
Teach your class how to solve problems using the triangle sum theorem. For this geometry lesson, young scholars identify the missing angles in a triangle using the sum theorem. They graph triangles on the TI and moves the sides around to...
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Worksheet
Curated OER

Triangles

For Students 6th - 10th
In this triangles worksheet, students solve six word problems where they determine the angles measures in different triangles.
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Worksheet
Curated OER

Angles in Polygons

For Students 10th - 12th
In this angles in polygons learning exercise, students determine the value of a missing angle measure. They find the value of interior angles and exterior angles. Polygons include triangles, quadrilaterals, pentagons, and hexagons. This...
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Lesson Plan
Curated OER

Solving Problems Using Triangle Inequality Theorem

For Teachers 6th
Sixth graders investigate triangles and the inequality theorem. They will collaborate in groups to determine the length of a longest side of a triangle. Then relate the size of the triangle to its angles using protractors, yard sticks,...
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Lesson Plan
Curated OER

Triangle Inequality Theorems Investigation

For Teachers 9th - 10th
Students estimate and measure triangles. In this geometry lesson, students identify the relationship between three sides and a triangle. They use the inequality theorem to decide if a triangle will be formed or not.
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Lesson Plan
Curated OER

Investigation - Adrienne's Pattern Block Angles

For Teachers 5th
Fifth graders investigate possible solutions to a word problem. They explore properties of polygons and right angles. Students demonstrate proper angle measurement. Students discover patterns.
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Worksheet
Curated OER

Proofs

For Students 8th - 11th
In this geometric proof learning exercise, students compose 20 triangle congruency proofs. Students will decide if there is enough information in problems 1-6 to prove if any triangles are congruent. In problems 17 to 20, students use...
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Worksheet
Curated OER

Interior and Exterior Angles of Polygons

For Students 10th
In this angles of polygons worksheet, 10th graders solve and complete 18 different problems that include determining various interior and exterior angles. First, they determine the measure of various angles described in the first half of...
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Worksheet
Curated OER

Triangle Similarity

For Students 10th
In this triangle similarity activity, 10th graders solve and complete 12 different problems that include defining similar and 3 similar statements using only sides and angles. First, they determine if each pair of triangles shown are...
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Worksheet
Math Mammoth

Classify The Triangles

For Students 6th - 8th
In this math activity, students measure all the angles in these triangles. They also calculate the sum of the angles and classify the triangles.
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Lesson Plan
Curated OER

Geometric Properties

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

Art or Junk? Discovering the Triangle Inequality

For Teachers 6th
Middle schoolers study the triangle inequality. They will identify, compare, and analyze attributes of two and three-dimensional shapes. Then they develop vocabulary to describe the attributes. They also use manipulatives to analyze the...