Lesson Plan
Curated OER

Proving Triangles Congruent

For Teachers 10th - 12th
Students examine Triangle Congruency. In this measurement comparison lesson, students use inductive, deductive and analytical thinking skills to prove triangle congruency. Students analyze and record their findings on activity worksheets.
Worksheet
Curated OER

Mid-Segment of a Triangle

For Students 10th - 11th
In this triangle worksheet, students examine triangle diagrams. They determine the perimeter, length of a line, midpoint of a line, and angle measurement from given information. This one-page worksheet contains ten problems.
Lesson Plan
Curated OER

Triangles in Architecture

For Teachers 10th - 12th
Students find triangles in the real world. In this geometry lesson, students analyze and identify properties of two and three-dimensional objects. They differentiate between similarity and congruence.
Worksheet
Curated OER

Parts of Similar Triangles

For Students 10th
In this parts of similar triangles worksheet, 10th graders solve 6 different problems related to determining the value of various parts of similar triangles. First, they find the value of x in the 2 figures shown. Then, students find the...
Lesson Plan
Curated OER

Special Right Triangles

For Teachers 7th - 9th
Students identify the different parts of a right triangle. In this geometry instructional activity, students use the Pythagorean Theorem to identify missing sides and angles of a right triangle. They work with irrational and rational roots.
Worksheet
Math Mammoth

Angles in a Triangle 2

For Students 6th - 8th Standards
Youngsters draw specified angles when given measurements of other angles and discover traits of angles in similar triangles. This one-page worksheet contains six multi-step problems.
Lesson Plan
Houghton Mifflin Harcourt

Introducing the Concept: Triangles and Quadrilaterals

For Teachers 5th - 7th Standards
Guide your geometers through the process of constructing polygons. They learn how to draw triangles, squares, parallelograms, rectangles, rhombuses, and trapezoids with specified angles using a protractor and a ruler. The lesson plan...
Lesson Plan
Curated OER

Polygons

For Teachers 5th - 7th
Students investigate the concepts related to the study of polygons. They specifically look at how angles is related. The lesson includes specific examples and dialogue to be used by the teacher during direct instruction and independent...
Lesson Plan
Curated OER

Discover the Pythagorean Theorem

For Teachers 6th - 8th
Learners explore the Pythagoras theorem. In this geometry lesson, students make right triangles and identify the parts of the triangle. Learners complete measurements of the sides of the triangle.
Worksheet
Curated OER

Proofs

For Students 8th - 11th
In this geometric proof worksheet, 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 given...
Worksheet
Curated OER

Archimedes

For Students 7th - 8th
In this Archimedes worksheet, students complete and respond to 4 different problems related to different triangles. First, they find the midpoint of each side of a given triangle. Then, students connect the midpoints with the opposite...
Lesson Plan
EngageNY

Solving Problems Using Sine and Cosine

For Students 9th - 10th Standards
Concepts are only valuable if they are applicable. An informative resource uses concepts developed in lessons 26 and 27 in a 36-part series. Scholars write equations and solve for missing side lengths for given right triangles....
Instructional Video25:49
2
2
Flipped Math

Unit Circle and Radians

For Students 9th - 12th Standards
Measure angles is easy as pi. Pupils review special right triangles to find exact values for trigonometric functions. Scholars learn about radians and how they connect to measurements in degrees. They find exact and approximate values of...
Lesson Plan
West Contra Costa Unified School District

Law of Sines

For Teachers 10th - 12th Standards
One must obey the sine laws. A lesson introduces and derives the Law of Sines for non-right triangles. With examples that use the Law of Sines to determine unknown measures in triangles, the lesson checks to see if the Law...
Interactive
CK-12 Foundation

Basic Inverse Trigonometric Functions: Ladder

For Students 10th - 12th Standards
Lean a ladder against the wall to create an angle. Class members use an interactive application to determine the angle a ladder makes with the ground. Individuals respond to five questions using inverse trigonometric functions.
Assessment
Mathed Up!

Loci and Constructions

For Students 8th - 11th Standards
A General Certificate of Secondary Education math review has class members make basic constructions. Using a protractor and a ruler along with a compass, pupils develop drawings of triangles with given measurements. Scholars use their...
Instructional Video3:10
Corbett Maths

Hexagon Inscribed Within a Circle

For Students 8th - 12th Standards
Mark off the length of the radius around the circle. Using a compass, the presenter shows how to construct a regular hexagon in a circle. Pupils see how triangles formed in the hexagon are equilateral, allowing for the construction to...
Assessment
Concord Consortium

In Oz We Tryst

For Students 9th - 11th Standards
The shortest distance from point A to point B is a straight line, but measuring distance gets more complicated when there are three points! Given the location of three friends, individuals determine the best point for all three friends...
Interactive
Scholastic

Study Jams! Congruent Figures

For Students 4th - 7th Standards
There is more to congruency than just looking similar. Learn the difference and calculate the matching angles and sides to prove the congruence between figures. Lesson has step-by-step slides and follows with an assessment. 
Lesson Plan
Curated OER

How are Trig Ratios Used to Measure Triangle Sides

For Teachers 8th - 11th
Students identify the ratios of trig identities. In this geometry lesson, students solve the missing sides and angles of triangles using trig ratios. They relate the graphs and waves to real life scenarios.
Worksheet
Curated OER

Finding the Angle Measurements in Isosceles Triangles

For Students 9th
In this angles worksheet, 9th graders find the angle measurements in four isosceles triangles.  Two of these triangles are drawn inside a circle, where two of the sides of the triangles are formed by radii.
Worksheet
Curated OER

Chapter 4 - Objective 3.1 - Perimeter & Angle Measure

For Students 10th - 12th
In this perimeter and angle measure worksheet, students find the length of the side of triangles and rectangles from given information. They read story problems, write equations and solve the problem. This one-page worksheet contains...
Worksheet
Curated OER

Geometry and Triangles

For Students 11th - Higher Ed
For this geometry triangles worksheet, students first determine how many degrees are found in one half and in three-fifths a revolution. Then they find the supplement of the two angles given and the radius of a circle. Students also...
Worksheet
Curated OER

Identify Similar Triangles With Proofs

For Students 10th - 12th
In this similar triangle instructional activity, students write a two-column proof to explain why determined triangles are similar. Given some line lengths and angle measurements, students use proofs to identify the ratio of specified...