Curated OER
Triangles
Students discover the difference between triangles. In this triangle lesson plan, students discuss the different types of triangles, then draw the three different types of triangles. The teacher will draw, or model, how to draw the...
Curated OER
Identifying Triangles
In this triangles practice activity, students respond to 4 questions that require them to identify the pictured triangles as acute, right, or obtuse triangles.
Curated OER
Triangles
In this triangle worksheet, students solve a set of 6 riddles involving the length of triangles and identifying types of triangles.
Curated OER
Triangles
In this triangles activity, 10th graders solve 12 different problems that include various angles of triangles. First, they determine the measure of an exterior angle. Then, students determine the measure of any of the base angles of an...
Curated OER
Ratios in Right Triangles
Learners calculate the sides of right triangles in this trigonometric ratios lesson. They use Cabri Jr. software and TI-83 or TI-84 calculators to find the side lengths and their ratios to each other for various triangles. The provided...
Exploratorium
The Four-Square Quilt
Youngsters recognize that triangles can be combined together to make various shapes. The learning activity provides a series of seven steps that engage children in applying transformations to triangles. Pupils use a quilt template and...
Curated OER
Basic Right Triangles
Elementary schoolers examine the attributes of triangles. In this triangle lesson, learners compare regular triangles and right triangles. They explore vertices and angles and investigate obtuse and acute angles. Pupils draw multiple...
Curated OER
Similar and Congruent Triangles
Learners create and classify different types of triangles using an online geo-board. They explore the concepts of similar and congruent as they discover how to draw similar and congruent triangles.
Curated OER
Exterior and Interior Angles of Triangles
Tenth graders explore the exterior and interior angles of triangles. They use a theorem in order to prove a theorem about all polygons. Students use the theorem and its applications to find the angles of different types of triangles.
EngageNY
The Definition of Sine, Cosine, and Tangent
Introduce your classes to a new world of mathematics. Pupils learn to call trigonometric ratios by their given names: sine, cosine, and tangent. They find ratios and use known ratios to discover missing sides of similar triangles.
Concord Consortium
Always, Sometimes, Never
Do your learners always, sometimes, or never remember the properties of the segments in triangles? Get that number closer to always with a creative lesson analyzing all four segments. Scholars consider a statement about one of the...
Curated OER
The Truth About Triangles And Proofs
Learners engage in a lesson that is about the classification of triangles and the mathematical proofs involved in working with them. They work on a variety of problems that are created by the teacher with the focus upon the importance of...
Curated OER
Exploring the Circumcenter of a Triangle
Students construct the circumcenter of a triangle. In this constructing the circumcenter of a triangle lesson, students construct a triangle using Cabri Jr. Students draw perpendicular bisectors of the sides of the triangle. Students...
Curated OER
Algebra/Geometry Institute Summer 2009 - Triangles and the Pythagorean Theorem
Seventh graders find the perimeter and area of triangles. In this finding the perimeter and area of triangles lesson, 7th graders find the perimeter and area of triangles given two sides. Students find the missing side by using the...
Curated OER
Nested Similar Triangles
Nested triangles have been created so that they share a common vertex and vertex angle. Learners drag the endpoints of the side that is opposite the common angle to discover the conditions that make the nested triangles similar. When...
Curated OER
Triangle Sum Theorem
Teach your class how to solve problems using the triangle sum theorem. For this geometry lesson, young scholars identify the missing angles in a triangle using the sum theorem. They graph triangles on the TI and moves the sides around to...
Curated OER
Circumscribing a Circle About a Triangle
Pupils circumscribe a circle about a triangle. They construct a triangle using Cabri Jr and then circumscribe it. They then use knowledge of perpendicular bisectors and circumcenters to locate the center of the circle and then...
Curated OER
Investigating Segments in a Right Triangle
High schoolers explore the concept of right triangles as they construct a right triangle using Cabri Jr. Learners find the midpoint of the hypotenuse and construct a line from the midpoint to the vertex of the right angle. They then...
Curated OER
Exploring the Orthocenter of a Triangle
Young mathematicians explore the concept of triangles as they construct altitudes of triangles to find the orthocenter. Learners construct their triangles using Cabri Jr. on their graphing calculators and find that the altitudes of a...
Curated OER
Right Triangles
In this right triangles worksheet, 10th graders solve and complete 14 various types of problems. First, they find the perimeter of the isosceles trapezoid shown. Then, students find the measures of each marked side of a right triangle....
Curated OER
Right Triangles
In this right triangles worksheet, 10th graders solve and complete 12 various types of problems. First, they solve for x given each of the right triangles shown. Then, students determine the length of the shorter diagonal given the...
Curated OER
Kuta Software - Infinite Geometry: Similar Triangles
In this similar triangles worksheet, students solve 20 short answer problems. Students determine if two given triangles are similar. Students determine the type of similarity given two triangles. Students are given a sketch of the...
Curated OER
Triangle Inequality Theorem
High schoolers investigate the relationship between angle measures and sides of a triangle and the relationships among the three sides of a triangle. The use of technology (Cabri, Jr.) allows learners to make and test conjectures as they...
Curated OER
Investigating Segments in a Triangle
Pupils investigate segments in a triangle by constructing a triangle using Cabri Jr. They construct segments within the triangle that lie on the midpoints of the triangle's sides. Learners then compare the slope of base of the triangle...