EngageNY
An Area Formula for Triangles
Use a triangle area formula that works when the height is unknown. The eighth installment in a 16-part series on trigonometry revisits the trigonometric triangle area formula that previously was shown to work with the acute triangles....
Alabama Learning Exchange
What You Know About the Bermuda Triangle?
Get lost in the classifications. Using the backdrop of the Bermuda Triangle, pupils classify it by angle and side measures. They also learn information about the triangle and its history.
Curated OER
Acute Triangles
Learners study acute triangles. They measure angles using a protractor, then classify the triangles as either right, obtuse, or acute. Everyone creates a design for a Navajo rug using only acute triangles.
Curated OER
Geometry of Triangles - Week 6
In this triangle worksheet, learners 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.
Curated OER
Special Segments of Triangles Jigsaw Activity
Students identify the special segments of triangles, the median, angle bisector, altitude, and perpendicular bisectors.
Curated OER
Travel Triangles
Students demonstrate and understanding of the three types of angles using triangles and quadrilaterals. In this angles lesson plan, students learn about acute, obtuse and right angles. They use cut-outs to find the areas of triangles and...
Curated OER
Triangle Attributes and Measures
Seventh graders explore the concept of triangles. In this triangles lesson, 7th graders sort triangles according to various attributes such as acute, obtuse, isosceles, or equilateral. Students find the area and perimeter of triangles.
Curated OER
Classifying Triangles Based On Properties of Angles
The interactive lesson featured here calls for the use of a Smartboard for sorting and classifying shapes. Then, pupils discuss the rules they followed for sorting their shapes, particularly focusing on the properties of angles. While...
Curated OER
Geometry of Triangles - Week 6
In this geometry of triangles worksheet, learners 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
Review of Triangles
Students investigate the Pythagorean Theorem. In this geometry lesson, students define angles and sides of right triangles. They calculate the area and surface area using formulas derived by the Pythagorean Theorem.
Curated OER
Pythagorean Theorem: Triangles and Their Sides
Learners investigate triangles and their relationship to each other. In this geometry lesson, students solve right triangles using the properties of the Pythagorean Theorem. They differentiate between right, acute, straight and oblique...
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.
Virginia Department of Education
The Pythagorean Relationship
Add up areas of squares to discover the pythagorean relationship. Small groups create right triangles with squares along each side. They calculate the areas of each square and notice the relationship. Groups construct other types of...
Curated OER
Pythagorean Theorem
Young scholars investigate the concept of the Pythagorean Theorem. After conducting independent practice to find the hypotenuse of a triangle, they work with the teacher using examples in the lesson plan. The direct instruction is...
Curated OER
Exploring Special Segments in Triangles
Students discover that four special segments have a common intersection point. They identify the position of the intersection point in triangles. They produce conjectures about areas of the divided triangles.
Curated OER
Geoboard Ideas
Students build polygons on their geoboards. In this geometry lesson plan, students build and then draw it on paper and label it. Students then switch with a partner to try an make a symmetrical shape.
Curated OER
Pythagorean Relationships
Oh that Pythagorean Theorem is so useful. Learners engage in a 45 minute learning activity that requires them to solve for missing angles and sides of a right triangle. They'll use the Pythagorean Theorem to find the rations of sides and...
Curated OER
Fashion Day
Eighth graders practice using basic measurements to solve word problems.They also investigate finding the perimeter of different polygons and define the characteristics to classify the shape as a polygon.
Curated OER
The Centroid : Balancing the History
Students discover the centroid of a triangle based on Euclid's constructions. They explore locus of points of a median. They understand properties of the segments that form the median and areas of the smaller sections formed by the median.
Curated OER
Geometry and Measurement
Learners view a right triangle displayed by the teacher. Students measure legs and the interior angles of the triangle. They look for a pattern or relationship between the legs and angles. Learners use pegboards and string to create more...
Curated OER
Geometry Review
Seventh graders explore basic geometric definitions involving angles, area, and circumference. To reinforce basic geometric concepts, they play a "lightning Flash" card game. Students discuss chores or jobs that require the use of...
Curated OER
Simple Angles
Third graders identify and construct right, acute and obtuse angles and begin to appreciate the degree and unit of measurement of angle. They know the degree value of angles that are simple fractions of a whole turn know that the angle...
Curated OER
Geometry w/o Figures - Week 7 (Basic Geometry Formulas)
In this basic geometry worksheet, students use basic formulas of geometry to find the area of a polygons, the number of sides of a polygon, and sum of the angles of various polygons. This three-page worksheet contains eight problems.
Curated OER
Pythagorean Theorem by Graphic Manipulation
There are many different ways to show a proof of the Pythagorean Theorem. Here is a nice hands-on paper cutting activity that shows a graphic representation. You can even challenge your young Pythagoreans to come up with their own...