Lesson Plan
Curated OER

Triangle Conjectures

For Teachers 10th
Tenth graders investigate the theorems of ASA, AAS, AAA and ASA. For this geometry lesson, 10th graders discuss the theorems of triangles and how it is used to solve for missing sides or angles. They review how two angles are formed by...
Lesson Plan
Key Curriculum Press

Triangle Inequalities

For Teachers 8th - 11th Standards
Properties about triangles are explored in this lesson. Geometers make conjectures about the length of a triangle's sides, the length of the angles in relation to the length of the sides, and the measure of the exterior angles of a...
Worksheet
Curated OER

Right Triangle Trigonometry

For Students 12th
For this trig worksheet, 12th graders identify the angles of a tight triangle using sine, cos and tan combined with the given sides. There are 23 problems broken down in 4 sections.
Lesson Plan
Curated OER

Triangle Sum Theorem

For Teachers 10th
Tenth graders investigate the theorems of angles and lines to prove triagle sum theorem. For this geometry lesson, 10th graders discuss the theorems of triangles and how it is used to solve for missing sides or angles. They review how...
Lesson Plan
Curated OER

Indirect Measurement

For Teachers 9th - 10th
Students measure and apply their knowledge of proportion to solve problems. In this geometry lesson plan, students measure using a meter stick, small mirror and measuring tape. They compare and contrast their measurements to objects...
Worksheet
Curated OER

Geometric Shapes and Angles

For Students 10th
In this geometry activity, 10th graders review polygons and solve for the missing angles of trapezoids and isosceles triangles. There are 10 questions on this activity with an answer key.
Lesson Plan
Curated OER

Triangles Congruency Theorems

For Teachers 10th
Tenth graders investigate the theorems of ASA, AAS, AAA and ASA. In this geometry lesson, 10th graders discuss the theorems of triangles and how it is used to solve for missing sides or angles. They review how two angles are formed by...
Lesson Plan
Texas Instruments

Cabri Jr. Inscribed and Central Angles

For Teachers 9th - 12th Standards
Learners will differentiate between inscribed and central angles in this geometry instructional activity. They answer questions dealing with circles as they relate to inscribed triangles and angles. This assignment includes a printable...
Worksheet
Curated OER

Using Trinonometry to Find Angle Measures

For Students 10th - 12th
In this trigonometric ratios worksheet, students find the missing angle of 20 triangles by using sine, cosine and tangent ratios. Students compute the angle measurement of given ratios for six problems.
Worksheet
Curated OER

7th Grade Mathematics Booklet

For Students 7th
In this 7th grade mathematics compilation worksheet, 7th graders solve and complete 40 various types of mathematics problems. They determine the measure of various angles and the side-lengths in integers of a square. Students also...
Worksheet
Curated OER

Pythagorean Theorem and Triangles

For Students 11th
In this geometry worksheet, 11th graders solve problems with right triangles using the Pythagorean Theorem. They find the missing angle or missing side. There are 15 questions with an answer key.
Lesson Plan
Curated OER

IGD: Perpendicular Bisector

For Teachers 9th - 12th
Students draw perpendicular bisectors.  In this perpendicular bisectors lesson, students identify the perpendicular bisector in a polygon.  They use web tools to create and measure perpendicular bisectors.  Students...
Handout
El Paso Community College

Geometry Definitions

For Students 7th - 9th Standards
Geometry is full of shapes, figures, and corresponding things here and there. The guide shares all of the key pieces of geometric information in a nicely color-coded and labeled sheet. 
Lesson Plan
Alabama Learning Exchange

Is It a Triangle?

For Teachers 9th - 12th Standards
Students explore the concept of triangle inequalities.  For this triangle inequality lesson, students cut spaghetti noodles into given lengths.  Students use the noodles to complete a worksheet about triangle...
Lesson Plan
Curated OER

Triangle Explorer

For Teachers 3rd - 6th
Students compute the area of triangles in a computer program. In this measurement lesson plan, students complete 5 easy, 5 medium, and 5 hard problems.
Lesson Plan
Curated OER

Simply Similar at Sea: Simple Triangles

For Teachers 10th
Tenth graders answer a variety of problems based on similar triangle and learn about the rule of thumb. They will test the rule of thumb by estimating the distance to an object in the classroom.
Lesson Plan
Curated OER

Congruent Triangles - Is This Enough Information?

For Teachers 7th
Seventh graders examine congruence postulates and apply knowledge to triangles in the world around them.
Lesson Plan
Curated OER

Triangle Explorer

For Teachers 3rd - 5th
Students calculate the area of triangles using a variety of materials including computer applets.
Worksheet
Curated OER

Angles

For Students 6th - 7th
In these angles worksheets, students complete several activities for angles. Students complete 34 problems about angle measurement.
Worksheet
Curated OER

Types of Triangles

For Students 4th - 5th
In this math worksheet, students classify the listed triangles and practice labeling them correctly. The definition of each type is necessary prerequisite knowledge.
Worksheet
2
2
K12 Reader

Shapes on a Plane

For Students 2nd - 3rd Standards
Geometric shapes are the focus of a comprehension exercise that asks readers to examine a short passage about planes, circles, triangles, and rectangles, and then to respond to a series of questions about the article.
Lesson Plan
EngageNY

Converse of the Pythagorean Theorem

For Students 8th Standards
Discover a new application of the Pythagorean Theorem. Learners prove and apply the converse of the Pythagorean Theorem in the 17th instructional activity in a 25-part series. The examples ask learners to verify right triangles...
Interactive
National Council of Teachers of Mathematics

Scale Factor

For Students 6th - 12th Standards
Does doubling mean everything doubles? Learners adjust the scale factor between two rectangles. Using the calculated measurements, pupils investigate the ratios between the lengths, perimeters, and areas of the rectangles.
Lesson Plan
EngageNY

Putting the Law of Cosines and the Law of Sines to Use

For Teachers 11th - 12th Standards
Use the Law of Cosines and the Law of Sines to solve problems using the sums of vectors. Pupils work on several different types of real-world problems that can be modeled using triangles with three known measurements. In the process,...