Introduction to history

Concept Map

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Additional Resources

OER

• Web resources:
  • Wikipedia, the free encyclopedia

• Books and journals
• Textbooks
• NCERT Textbooks – Class 11
  • Karnataka Govt Text book – Class 11

• Syllabus documents

Non-OER

• Web resources:
  • Historical thinking : blurb
• 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

Teaching Outlines

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: A plane figure formed by three intersecting lines.
2. Elements of a triangle: Terms that are associated with triangle.
3. Measures in triangle: Parameters that are measured in a triangle.
4. Interior and exterior angles in triangle: Angles formed when a triangle is formed.

Concept 2: Types of triangles based on sides and angles

Types of triangles based on angles in the triangle

1. Acute triangles are triangles in which the measures of all three angles are less than 90^o.
2. Obtuse triangles are triangles in which the measure of one angle is greater than 90^o.
3. Right triangles are triangles in which the measure of one angle equals 90 degrees.

Types of triangles based on sides in the triangle

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: Triangles formed are dependent on measures of sides.
2. Types of triangles based on angles: Triangles formed are dependent on measures of angles.

Concept 3: Angle sum property

Activities

1. Angle sum property:

Concept 4: Relation between interior and exterior angles in triangle

Activities

1. Relation between interior and exterior angles in triangle