Lesson Plan
Illustrative Mathematics

Area of a Trapezoid

For Teachers 7th - 9th Standards
Here is a straightforward example of how to apply the Pythagorean Theorem to find an unknown side-length of a trapezoid. Commentary gives additional information on proving that the inside of the trapezoid is a rectangle, but is...
Assessment6:43
Mathed Up!

Angles in Triangles and Quadrilaterals

For Students 8th - 10th Standards
This short video show viewers how to connect the sum of the angles in a triangle to other angle measurements. Pupils determine the missing measures for angles involved with triangles and quadrilaterals. Class members then must explain...
Worksheet
Curated OER

Walking to Make a Triangle

For Students 9th - 12th
In this word problem worksheet, high schoolers solve 1 multiple choice word problem.  Students determine the distance one must travel to complete a triangle.
Interactive
CK-12 Foundation

Logarithms: Logarithm Triangle

For Students 10th - 12th Standards
Study logarithmic properties using a triangle. A clever manipulative shows how a triangle can represent the three parts of a logarithmic or exponential equation. Pupils review the concept and then answer guiding questions to further...
Activity
Bethel School District

Health Triangle Self Assessment

For Students 7th - 12th
Measure health as a triangle, with each side representing different aspects of health: physical, emotional/mental, and social. High schoolers complete a self-assessment of their health in all three areas before scoring their progress and...
Worksheet
Curated OER

Types of Triangles

For Students 2nd - 4th
Young math whizzes solve four problems in which a triangle with labeled angle measurements is analyzed. They mark if each triangle is acute, right, or obtuse.
Organizer
Curated OER

Triangles

For Students 3rd - 7th
In this geometry worksheet, students will answer questions to determine if a shape is a triangle and if so, what type of triangle.
PPT
Curated OER

Counting Triangles

For Teachers K - 1st
Help your little learners recognize number words one through ten. Each slide contains a triangle with a number word inside of it. As the slides progress, more triangles appear in successive order 1-10. This is a great way to reinforce...
Interactive
Curated OER

Triangle Problems-Base, Height, and Area

For Students 10th
For this geometry worksheet, 10th graders find the base, height, or area of a triangle. The one page interactive worksheet contains ten questions. Answers and hints are included. 
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 instructional activity.
Lesson Plan
Alabama Learning Exchange

Triangle Congruence with Rigid Motion

For Students 9th - 12th Standards
Combine transformations and triangle congruence in a single activity. Scholars learn to view congruent triangles as a rigid transformation. Using triangle congruence criteria, learners identify congruent triangles and the rigid...
Lesson Plan
1
1
Illustrative Mathematics

Right Triangles Inscribed in Circles II

For Teachers 9th - 10th Standards
So many times the characteristics of triangles are presented as a vocabulary-type of lesson, but in this activity they are key to unraveling a proof. A unique attack on proving that an inscribed angle that subtends a diameter must be a...
Lesson Plan
Alabama Learning Exchange

Triangle Area: No Height? Use the Sine

For Students 9th - 12th Standards
No height? No problem! Learners use their knowledge and a little help from GeoGebra to develop the Law of Sines formula. The Law of Sines helps to determine the height of triangles to calculate the area.
Printables
PreKinders

A World of Shapes

For Teachers Pre-K - K
There are shapes everywhere you see! Use a presentation about shapes to encourage young learners to find squares, circles, triangles, and rectangles in a series of pictures. One slide shows kids what the shapes look like, and then a...
Lesson Plan
Curated OER

Sum of Angles on a Triangle

For Teachers 4th - 5th
Use this lesson for a basic review of angles. While the activities discussed are outlined, there are no materials provided to make implementation possible. When using this resource, it is necessary to create worksheets and other...
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,...
Lesson Plan
Curated OER

Triangle Inequality

For Teachers 4th - 6th
Students discover that the sum of the lengths of any two sides of a triangle must be greater than the third side. They are shown how a triangle is formed using three strips such as that the triangle is seen inside the strips.
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

Triangle Inequality Theorems Investigation

For Teachers 9th - 10th
Students estimate and measure triangles. In this geometry instructional activity, 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.
Lesson Plan
Curated OER

Midsegments of a Triangle

For Teachers 9th - 12th Standards
Students analyze midsegments of triangles in this lesson. They use Cabri Jr. software to observe the relationships between interior angles and midsegments of triangles. Specific instructions for creating this lesson in Cabri Jr. are...
Lesson Plan
Curated OER

Angles of a Triangle

For Teachers 9th - 12th Standards
Learners explore the measures of the angles of a triangle in this geometry lesson. They use Cabri Jr. to investigate the sum of the measures of the interior angles of a triangle, and examine the relationships between the interior and...
Interactive
Curated OER

Angles in a Triangle

For Students 9th - 12th
In this online math worksheet, students calculate the angles in a triangle given their measurements. This excellent resource allows the students to check their answers, and to get "hints" should they run into difficulties. A terrific...
Worksheet
K12 Reader

Classifying Triangles

For Students 2nd - 3rd Standards
Bring math and reading informational text together with a reading comprehension lesson. After kids read about isosceles, scalene, and equilateral triangles, they answer five comprehension questions to demonstrate how they can use context...
Printables
K-5 Math Teaching Resources

Triangle Pack

For Teachers 4th - 6th Standards
With so many different types of triangles, it can be a challenge for young mathematicians to keep them all straight. Luckily this set of printable triangles is here to engage children in comparing and sorting triangles by their...

Other popular searches