Lesson Plan
Virginia Department of Education

Special Right Triangles and Right Triangle Trigonometry

For Teachers 9th - 11th Standards
Right triangles are so special! Use special right triangles to discover the trigonometric ratios. Pairs construct special right triangles and find the values of the ratios of the sides. In the process, they discover the ratios stay the...
Worksheet
Curated OER

Isosceles Right Triangle

For Students 10th
In this isosceles right triangle worksheet, 10th graders solve and complete 5 different constructions of composition and decomposition. First, they make 4 congruent isosceles triangles with the model on the left. Then, students create...
Worksheet
Curated OER

Right Triangles

For Students 10th
In this right triangles worksheet, 10th graders solve and complete 12 various types of problems. First, they solve for x given each of the right triangles shown. Then, students determine the length of the shorter diagonal given the...
Worksheet
Curated OER

Area of Right Triangles

For Students 8th - 10th
In this are of right triangles worksheet, students read graphs and explore congruent triangles.  They find the area of rectangles and of right triangles.  This one-page worksheet contains explanations, instructions, and 8...
Worksheet
Curated OER

Special Right Triangles Homework

For Students 9th - 12th
In this geometry instructional activity, high schoolers solve both kinds of special right triangles. There are 12 questions with multiple parts.
Assessment
Mathematics Assessment Project

Hopewell Geometry

For Students 8th - 10th Standards
Right triangles from 2,000 years ago? Learners investigate different right triangles found in the earthworks of the Hopewell people, a Native American culture that populated the United States from 200BC to AD 500. Learners apply concepts...
Lesson Plan
Curated OER

Finding the Area of an Equilateral Triangle

For Teachers 9th - 11th Standards
The problem seems simple: find the area of the equilateral triangle whose sides are each length 1. In fact, this same problem is solved in 8th grade, addressing a different Common Core standard, using the formula for area of a triangle...
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.
Worksheet
Curated OER

Finding Angles in Right Triangles

For Students 10th
In this geometry activity, 10th graders use right triangle trigonometry to solve application problems in which they find the measure of the missing angle in a right triangle.  The two page activity contains five free response...
Lesson Plan
Curated OER

Applying Special Right Triangles

For Teachers 10th
In this geometry worksheet, 10th graders use the theorems regarding right triangles to find the missing length in a special right triangle. The one page worksheet contains eleven questions. Answers are included.
Assessment
Inside Mathematics

Hopewell Geometry

For Teachers 9th - 12th Standards
The Hopewell people of the central Ohio Valley used right triangles in the construction of earthworks. Pupils use the Pythagorean Theorem to determine missing dimensions of right triangles used by the Hopewell people. The assessment task...
Assessment
Inside Mathematics

Circles in Triangles

For Teachers 9th - 12th Standards
Challenge the class with inscribed circles in triangles. The assessment task requests class members use their knowledge of circles and right triangles to prove two triangles are congruent. They go on to utilize their knowledge of...
Interactive
Curated OER

Mixed Right Triangles

For Students 10th
In this geometry worksheet, 10th graders use right triangle trigonometry to find the missing angle measure or side length in right triangles. The one page interactive worksheet contains ten questions. Answers and hints are included. 
Worksheet
Curated OER

Right Triangles

For Students 10th
In this right triangles worksheet, 10th graders solve and complete 12 different types of problems. First, they solve for a variable given each of the right triangles with the sides as indicated. Then, students determine the shorter...
Worksheet
Curated OER

Right Triangles

For Students 10th
In this right triangles worksheet, 10th graders solve 10 different problems that include determining the means proportionally in each right triangle. First, they use the given information to determine the measure of each line segment....
Worksheet
Curated OER

Right Triangles & Pythagorean Theorem

For Students 6th - 8th
In this math worksheet, students find the missing angles for the right triangles using the Pythagorean Theorem. Then they label the adjacent and opposite angles.
Lesson Plan
EngageNY

The Converse of the Pythagorean Theorem

For Teachers 8th Standards
Is it a right triangle or not? Introduce scholars to the converse of the Pythagorean Theorem with a lesson that also provides a proof by contradiction of the converse. Pupils use the converse to determine whether triangles with given...
Worksheet
Curated OER

Determine the Measure of an Angle of a Right Triangle.

For Students 10th - 11th
In this geometry instructional activity, students solve word problems by finding the values of missing angles and missing sides of triangles. They review their trigonometric properties of a right triangle. There are 9 problems with an...
Worksheet
Curated OER

Classifying Triangles Using Sides

For Students 4th - 5th
In this geometry learning exercise, students answer 8 fill in the blank questions where they must examine 5 different complex geometric figures to classify triangles.
Worksheet
Curated OER

Similar Right Triangles-Introductions to Trigonometry

For Students 9th - 10th
In this geometry worksheet, students examine similar right triangles as the basis for the foundation of trigonometry. Students define the basic trigonometric functions and use a calculator to find the trigonometric value of an angle. The...
Worksheet
Curated OER

Right Triangle

For Students 8th - 9th
In this right triangle activity, students find the length of sides of a right triangle. This one-page activity contains 1 problem.
Worksheet
Curated OER

Right Triangle

For Students 8th - 9th
In this right triangle worksheet, students find the lengths of the sides of a triangle. This one-page worksheet contains 1 problem.
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...
Handout
McGraw Hill

Triangles

For Students 4th - 7th Standards
After reviewing characteristics of seven types of triangles, young geometers discover how to find the missing angle of a triangle. Then, they practice identifying triangles, find missing angles, and find missing side lengths of...