EngageNY
Unique Triangles—Two Sides and a Non-Included Angle
Construct an understanding of triangle congruence through a visual analysis. Young scholars find that given two sides and a non-included angle, sometimes two possible triangles are produced. Their analysis shows that if the non-included...
Curated OER
Measuring Angles
Solve and complete 18 problems about angles. First, demonstrate that each conjecture is false by giving a counterexample. Then write the inverse, contrapositive, and converse for the each statement. In addition, write a...
K12 Reader
Shapes on a Plane
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.
University of Exeter
Angles and Turns
Junior geometers investigate the concepts of angles and turns using straws to perform a hands on activity. This is helpful for kinesthetic learners who have a hard time with mathematics. The lesson plan includes the dialogue to be used...
Noyce Foundation
Parallelogram
Parallelograms are pairs of triangles all the way around. Pupils measure to determine the area and perimeter of a parallelogram. They then find the area of the tirangles formed by drawing a diagonal of the parallelogram and compare their...
Flipped Math
Reference Triangles
It is all about where the side is located. Pupils use their knowledge of angles in standard position to find reference angles. They use the Pythagorean Theorem to find lengths along a terminal side of an angle to determine the exact...
Radford University
Right Triangle Sports
Who knew math could help with sports? An invigorating set of lessons encourages learners to apply right triangles in baseball, volleyball, hockey, football, and soccer. They use the Pythagorean Theorem, Pythagorean triples, special right...
EngageNY
Unknown Angle Proofs—Proofs of Known Facts
Lead the class in a Greek history lesson with a geometric twist. Pupils relate a short video about geometric properties to modern-day methods of solving for unknown angles. They discuss parallel line theorems and complete...
Radford University
Developing a Trigonometry Phone App
What's one more app? After reviewing how to calculate missing side lengths or angle measures in a right triangle, pupils create instructions for a phone app to do all of the tedious work. They must consider all nine cases of known...
Curated OER
Academic Grade 9 Assessment of Mathematics: Algebra I and Geometry
Test your class, or use this 12 page math packet as chapter review. They solve 21 multiple choice problems which require them to graph linear equations, find the volume of prisms and cones, find unknown angles, and determine...
Mathed Up!
Area of Sector and Length of Arcs
Viewers learn how to apply proportional reasoning to find area of sectors and arc lengths with a video that starts off explaining how to find the areas of circle sectors and the lengths of arcs. Scholars then practice solving problems...
Curated OER
Student Reading - The Unique Properties of Water
Without water there would be no life on this planet. Biology learners find out why by reading this handout. Create a worksheet of questions to answer after the reading. Follow it up with quick demonstrations or laboratory activities that...
Curated OER
Triangles and Congruence
Can your class construct triangles and determine congruence? Find out with this well put together worksheet. THey construct triangles to given specifications and identify if they are congruent. There are 3 muti-step problems to solve.
Curated OER
Triangle Designs
In this triangles worksheet, students draw different triangles and write how many sides and angles each one has. Students draw 4 kinds of triangles and have 2 that are impossible to draw.
Curated OER
Archimedes
For 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...
Curated OER
Angle-Side Relationships
Students calculate the different sides and angles of a triangle. In this geometry lesson, students use triangular properties to define the relationship between two triangle. They identify missing angles using the interior angle theorem.
Curated OER
Bisectors of Triangles
In this geometry worksheet, 10th graders solve problems involving the perpendicular bisectors and angle bisectors of a triangle and their points of concurrency. The one page worksheet contains sixteen questions. Answers...
Curated OER
Similar Triangles
Students differentiate between similar and congruent triangles. For this geometry lesson, students identify the missing side and angle of a triangle. They identify the different ratio and proportion of the sides of a triangle.
Key Curriculum Press
Triangle Inequalities
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...
Curated OER
Triangle worksheets
In this geometry worksheet, 10th graders explore triangle properties, including the sum of the measures of the angles of a triangle, the triangle inequalities, properties of isosceles triangles, properties of congruent triangles, and...
Curated OER
Inscribed Angles
Students calculate the inscribed angle of a triangle. In this geometry lesson, students identify the angle created by intersection of a triangle and a circle. They see the relationship between the arc and the angle.
Curated OER
Reflections Of
Students create angles using mirrors. In this angle reflection lesson, students draw angles, then use mirrors to create angles using reflections and measure the new angles.
Mathed Up!
Sine and Cosine Rules and Area of Triangles
Learners discover how to find missing sides and angles using trigonometry. Scholars first watch a video covering the Law of Sines and Cosines, as well as the area formula for a triangle. To test their knowledge, they complete a worksheet...
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...