Worksheet
National Council of Teachers of Mathematics

How Many Triangles?

For Students 5th - 8th
For this triangles worksheet, learners problem solve and shade triangles within other triangles. Learners complete two problems.
Worksheet
Curated OER

Tangrams

For Students 6th - 8th
In this tangram worksheet, middle schoolers form a square using tangrams.  Afterwards, they form additional shapes with tangrams.  This one-page worksheet contains 180 tangram shapes for students to create  by placing...
Worksheet
Curated OER

Find the Missing Side of the Right Triangle

For Students 6th - 8th
In this find the missing side of the right triangle worksheet, students use the Pythagorean theorem to find the missing side, given the other 2 lengths, for 4 triangles.
Worksheet
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The Law of Cosines

For Students 11th - 12th
For this Law of Cosines worksheet, students are asked to demonstrate the ability to apply the Trigonometric Law of Cosines and the Inverse Law of Cosines to solve for sides and angles of right triangles. 
Lesson Plan
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Pascal's Patterned Triangle

For Teachers 5th
Fifth graders receive a brief history of Pascal's triangle. As a class the students construct the first few rows of the triangle. The students are then split into groups where they finish a worksheet identifying the total value of each...
Lesson Plan
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The Greedy Triangle

For Teachers 3rd - 4th
Students discuss figures with various numbers of sides.  In this geometry lesson, students are read The Greedy Triangle by Marilyn Burns, they participate in a class discussion of many sided figures and are introduced to the term...
Worksheet
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Pythagorean Theorem for Algebra I

For Students 8th - 9th
In this Pythagorean theorem for algebra I instructional activity, learners answer 10 problems finding the missing side of a right triangle using the Pythagorean theorem.
Lesson Plan
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Drawing a Triangle with Cabri Junior

For Teachers 9th - 12th Standards
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...
Worksheet
Curated OER

Using Algebraic Equations in Geometry Problems

For Students 6th
In this using algebraic equations in geometry problems worksheet, 6th graders write an equation to solve each addition problem about geometry, then find the solution.
Worksheet
Print and Practice

Triangles and Rectangles

For Students K - 2nd
In this triangle and rectangle activity, students color triangles red and rectangles blue in a given set of shapes. A reference web site is given for additional activities.
Worksheet
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Pythagorean Theorem

For Students 7th - 10th
For this Pythagorean theorem worksheet, learners use the Pythagorean theorem to find the missing side of the triangle. Students complete 10 problems.
Worksheet
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Inverse Functions in Trigonometry

For Students 9th - 10th
In this inverse functions in trigonometry activity, students find the missing angles in eight right triangles, given the length of two sides.
Worksheet
Curated OER

Triangle: Print and Color

For Students Pre-K - 1st
In this word recognition learning exercise, students trace the word "triangle", write the word independently, and color the picture of the triangle.
Worksheet
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Using the Pythagorean Theorem

For Students 7th - 8th
In this using the Pythagorean Theorem instructional activity, students use the Pythagorean Theorem to find the missing information for ten right triangles.
Lesson Plan
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Formula Determination

For Teachers 9th - 12th
Students derive a formula for the interior degrees in any convex polygon. In this geometric figure lesson, students determine the shapes of various polygons and the number of triangles formed. They use this information to derive the...
Lesson Plan
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Altitude Locator

For Teachers 9th - 12th
Students use protractors, strings, and straws to construct a device used to determine the height of tall objects. In this applied geometry lesson, students use common objects to construct a tangent height guide. They use principles of...
Worksheet
Curated OER

Cosine

For Students 10th - 12th
In this cosine instructional activity, students find the cosine of x for different measurements of triangles. Students complete 10 cosine problems.
Lesson Plan
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Sine

For Teachers 10th - 12th
In this sine worksheet, learners use the trigonometry equation to find the sine of triangles. Students solve the sine for 10 triangle problems.
Worksheet
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Triangle Puzzle

For Students 2nd - 3rd
For this geometric shapes worksheet, students analyze an intricate design of lines. Students look for all the triangles and tell how many there are.
Lesson Plan
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Physics Lab Rockets

For Teachers 10th - 12th
Students construct and test balloon rockets and a model rocket. In this rocket science lesson, students use an inquiry-based method to master balloon rockets and have a shoot-off with the goal of attaining the highest altitude. Next,...
Lesson Plan
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Roll It! Creating an Entrance Ramp

For Teachers 9th - 12th
Students explore the concept of triangles.  In this triangles activity, students are to propose a plan for a ramp at their school.  Students use the Pythagorean Theorem and trigonometry to determine the length, height, and...
Worksheet
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Identify Triangles 2

For Students 2nd - 5th
In thins triangles review worksheet, students examine 4 triangles and their measurements. Students classify them as equilateral, isosceles, or scalene.
Worksheet
Curated OER

Identify Triangles

For Students 3rd - 5th
In thins triangles review worksheet, students examine 3 triangles and their measurements. Students classify them as acute, right, obtuse, equilateral, isosceles, or scalene.
Worksheet
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Drawing Triangles

For Students 6th
In this drawing triangles worksheet, 6th graders read the dimensions of four triangles, given the length or the angle, identify the type of triangle and draw it.