Triangles

=Concept Map =

=Additional Resources=

OER

 * Web resources:
 * 1) Bright Hub Education - Basic concepts of triangles,Types of triangles,Angle sum property,Exterior and interior angle relation
 * 2) Folioz - Inequalities in triangle, Investigate the relationship between the  sides and angles in a triangle
 * 3) JsunilTutorial - Test papers for triangles
 * Books and journals
 * Textbooks
 * NCERT Textbooks – Class 9
 * 1) Karnataka Govt Text book – Class 8
 * Syllabus documents

Non-OER
CPALMS -Introduction to triangles as a closed three sided figure,Inequalities in triangles
 * Web resources:
 * Books and journals
 * Textbooks
 * Syllabus documents (CBSE, ICSE, IGCSE etc)

=Learning Objectives=
 * Identify a triangle
 * Recognize interior and exterior angles
 * Classifying types of triangles
 * Recognize the angle sum property
 * Establish relation between interior and exterior angles

Concept #1. Formation of a triangle, elements of a triangle and its measures

 * 1) A triangle is a three sided closed figure.
 * 2) It is one of the basic shapes in geometry.
 * 3) It triangle is a polygon with three edges and three vertices.
 * 4) There are three angles in a triangle formed at the three vertices of the triangle.
 * 5) Interior and exterior angles in a triangle at a vertex, together form a linear pair.

Activities

 * 1) Formation of a triangle
 * 2) Elements of a triangle
 * 3) Measures in triangle
 * 4) Interior and exterior angles in triangle

Concept 2: Types of triangles based on sides and angles
Types of triangles based on angles in the triangle Types of triangles based on sides in the triangle
 * 1) Acute triangles are triangles in which the measures of all three angles are less than 90o.
 * 2) Obtuse triangles are triangles in which the measure of one angle is greater than 90o.
 * 3) Right triangles are triangles in which the measure of one angle equals 90 degrees.
 * 1) Equilateral triangles are triangles in which all three sides are the same length.
 * 2) Isosceles triangles are triangles in which two of the sides are the same length.
 * 3) Scalene triangles are triangles in which none of the sides are the same length.

Activities

 * 1) Types of triangles based on sides
 * 2) Types of triangles based on angles

Activities

 * 1) Angle sum property

Activities

 * 1) Relation between interior and exterior angles in triangle