National Security Agency
Classifying Triangles
Building on young mathematicians' prior knowledge of three-sided shapes, this lesson series explores the defining characteristics of different types of triangles. Starting with a shared reading of the children's book The Greedy Triangle,...
Mathed Up!
Angles
What does a geometric farmer drive? A protractor, of course! A set of assessment worksheets prompts learners to use a protractor as they measure angles, name angles, and identify lines. Use the video as a way to introduce the concepts.
Curated OER
Identify triangles
Students explore triangles. For this geometry lesson, students will create note cards with pictorial depictions of right, acute,obtuse, scalene, isosceles, equilateral and equiangular triangles. Students will verbally describe each type...
Curated OER
Identifying Triangles
In this triangles practice worksheet, students respond to 4 questions that require them to identify the pictured triangles as acute, right, obtuse, scalene, isosceles, or equilateral triangles.
Pennsylvania Department of Education
Kites: On the Right Track
Students use the Pythagorean theorem to discover the relationships between the lengths of sides of a right triangle. In this right triangles lesson plan, students use their reasoning and mathematical skills.
Curated OER
Solving Problems with Angles
Upper elementary math whizzes complete word problems having to do with measurements of angles. They complete 10 multiple choice problems.
Curated OER
The Greedy Triangle-Intro to Geometric Shapes
In this geometry lesson, learners read The Greedy Triangle and use geoboards to construct geometric shapes. They identify the number of sides and angles each shape has.
Curated OER
Identifying Triangles
In this geometry worksheet, 10th graders identify a triangle as right, acute, or obtuse and identify the parts of a right triangle in a drop and drag game format. The one page interactive worksheet contains eight matching questions and...
Houghton Mifflin Harcourt
Unit 5 Math Vocabulary Cards (Grade 6)
Acute angle, line of symmetry, and vertex are a few terms you'll find in a set of 90 flashcards designed to reinforce math vocabulary. Included in the set are two types of cards; a word card printed in bold font, and a definition card...
Curated OER
Triangle Attributes and Measures
Seventh graders explore the concept of triangles. In this triangles instructional activity, 7th graders sort triangles according to various attributes such as acute, obtuse, isosceles, or equilateral. Students find the area and perimeter...
Curated OER
Investigation - Adrienne's Pattern Block Angles
Fifth graders investigate possible solutions to a word problem. They explore properties of polygons and right angles. Students demonstrate proper angle measurement. Students discover patterns.
Houghton Mifflin Harcourt
Unit 6 Math Vocabulary Cards (Grade 5)
Acute angles, nets, and vertices are only a few terms that a set of flash cards includes. Among the 108 cards, two types are available; word cards printed in bold-faced lettering, and corresponding definition cards equipped with an...
Curated OER
Triangles Word Search
In this word search worksheet, learners locate 7 types of triangles. Triangles include isosceles, acute, equilateral, right, and obtuse.
Curated OER
Classifying Triangles
In this classifying triangles instructional activity, 10th graders solve 6 different problems related to the classification of triangles either by their angles or by their sides. First, they use a protractor and a ruler to draw triangles...
Curated OER
Independent Practice 2: Triangles
In this triangle worksheet, middle schoolers identify given triangles according to their sides and angles. Afterward, students draw triangles to match given descriptions. This one-page worksheet contains 15 problems.
Curated OER
Identifying Triangles
Sixth graders identify and define a variety of triangles. In this identification of triangles lesson, 6th graders draw examples of each triangle on a whiteboard, then complete a worksheet.
K-5 Math Teaching Resources
2-D Shape Cards
Add some visual support to your elementary geometry lessons with this set of printable shape cards. From triangles and squares to octagons and nanogons, this simple resource can be used in countless ways to develop children's knowledge...
Noetic Learning
Kinds of Triangles (Online Interactive)
In this triangles learning exercise, students analyze pictures of four triangles. For each triangle, students mark if it is acute, obtuse, or right.
Curated OER
Constructions and Angles
In this triangle constructing and classifying worksheet, students read through a tutorial on triangles and angles. Then, students complete 17 exercises in which they answer questions about angles and triangles. By clicking on the "Check"...
Curated OER
Orthocenter Of a Triangle
Students find the orthocenter of a triangle. In this geometry lesson, students identify where the altitudes meet in a triangle. They use Cabri software to explore acute, obtuse and right triangles.
Curated OER
Geometry of Triangles - Week 6
In this geometry of triangles worksheet, students find the length of sides, are, and angle measurement of inscribed triangles, pentagons, and midpoint of a line. This two-page worksheet contains seven problems.
Curated OER
Twenty-Five Measures of the Angles of a Triangle Problems
For this triangle worksheet, students calculate the measures of the angles or the sums of the measures of the angles in twenty-five triangle problems and hands-on activities. The solutions are provided.
Curated OER
Parts of Similar Triangles
In this parts of similar triangles worksheet, 10th graders solve and complete 15 different statements related to naming the parts found in similar triangles. First, they identify each definition stated that describes an everyday usage of...
Curated OER
Pythagorean Theorem
In this Pythagorean theorem worksheet, 9th graders solve and complete 6 various types of problems. First, they find the length of a right-angled triangle's hypotenuse. Then, students determine which triangle is described and explain...