CK-12 Foundation
Ck 12: Elem Math: Determining Whether Lines Are Perpendicular
[Free Registration/Login may be required to access all resource tools.] Students watch two videos and attempt practice problems on how to determine if two lines are perpendicular.
CK-12 Foundation
Ck 12: Elem Math: Determining Unknown Angles in Trapezoids
[Free Registration/Login may be required to access all resource tools.] Students watch a video overview and attempt practice problems on finding the missing angles in a trapezoid.
Alabama Learning Exchange
Alex: Geometric Man
The students will explore angles, rays, line segments, perpendicular lines, parallel lines, and two-dimensional figures through the use of the book Shape Up! Fun With Triangles and Other Polygons by David A. Adler. They will also...
Alabama Learning Exchange
Alex: A Triangle to Remember
This lesson will introduce students to different types of triangles by using a clip from the movie A Walk to Remember. They will take part in interactive tutorials to strengthen the concepts of classifying triangles. The students will...
Scholastic
Scholastic: Study Jams! Math: Geometry: Classify Angles
Watch and learn how to classify angles then test your knowledge.
National Council of Teachers of Mathematics
Nctm: Illuminations: Area of Triangles
To find the area of a triangle, try to make a parallelogram using a copy of the triangle.
Cuemath
Cuemath: Congruent Triangles
Explore the world of congruent triangles in this mini-lesson. Provides a definition and examples that help with understanding their properties. Includes a short video and practice questions with answers.
Math Open Reference
Math Open Reference: Scalene Triangle
Learn about scalene triangles with this helpful reference tool. Provides a detailed definition, examples, and an interactive activity that enhances further explanation. Includes links to related topics.
Homeschool Math
Homeschool Math: Area of Triangles
This lesson presents the idea that the area of any triangle is exactly half of a certain parallelogram -- thus we get the familiar formula of multiplying the base and the altitude and taking half of that. The lesson contains varied...
Quia
Ixl Learning: Types of Triangles
Brush up on your math skills relating to the types of triangles then try some practice problems to test your understanding.
The Math League
The Math League: Figures and Polygons
This website has basic definitions for most polygons, regular and irregular.
The Math League
The Math League: Isosceles Triangle
This site gives the definition of isosceles triangles.
The Math League
The Math League: Obtuse Triangle
This site gives the definition of obtuse triangles.
The Math League
The Math League: Scalene Triangle
This site provides the definition of Scalene triangles.
Mr. Martini's Classroom
Mr. Martini's Classroom: Teacher's Figure Library: Geometric Figures
This interactive resource provides an example picture of the geometric figure chosen by students to review.
Doina Popovici
Math Play: Classifying Triangles
Practice identifying triangles as either acute, right, or obtuse in this interactive game.
Other
Mathematics Internet Library: Free Internet Books
Practice problem worksheets are available for students needing to study basic terms relating to triangles and other math concepts.
ClassFlow
Class Flow: Quadrilaterals
[Free Registration/Login Required] This flipchart introduces students to quadrilaterals and how to classify them.
ClassFlow
Class Flow: Segments and Polygons
[Free Registration/Login Required] This flipchart reviews segments, parallel and perpendicular lines and then introduces polygons including quadrilaterals. It has many real world examples of shapes and includes Activote assessment.
ClassFlow
Class Flow: Triangles
[Free Registration/Login Required] Using this flipchart students learn to recognize and classify different triangles, including equilateral, isosceles and scalene. The teacher will use this lesson plan to review different types of...
ClassFlow
Class Flow: What Are Quadrilaterals
[Free Registration/Login Required] This flipchart introduces quadrilaterals Utilizing a United streaming video. The flipchart allows students to identify quadrilaterals that are polygons, real world shapes and how other objects contain...
ClassFlow
Class Flow: Angle This Way
[Free Registration/Login Required] Students will identify right, acute and obtuse triangles using many interactive tools available in ACTIVstudio 3.0. Students will be engaged using a magnifier tool, the fill tool, and drag and drop and...
ClassFlow
Class Flow: Angles
[Free Registration/Login Required] Practice identifying different types of angles in this flipchart. See examples of the different angles.