Introducing Angles in a Triangle

Introducing Angles in a Triangle
Introducing Angles in a Triangle
Introducing Angles in a Triangle

What's Included

  • Smart Notebooks Presentation
  • Activ Inspire Flipchart
  • Lesson Plan
  • Microsoft PowerPoint Presentation
  • Differentiated Worksheet

Introducing Angles in a Triangle

Building on angles on a straight line and vertically opposite angles students are taught why angles in a triangle have a sum of 180°.  More able students are challenged to prove this using angles in parallel lines.The start of the lesson recaps related angle properties such as those on a straight line and about a point.  The main part introduces the sum of angles in a triangle as 180° and provides several examples for practice.  The plenary challenges students to combine multiple properties within a single problem.
Differentiated Learning Objectives
  • All students should be able to calculate angles in a scalene triangle.
  • Most students should be able to calculate angles in an isosceles triangle and combine other angle properties.
  • Some students should be able to prove angles in a triangle have a sum of 180°.
Lesson Downloads
Download Lesson Plan Download PowerPoint Download Notebook Download Flipchart Download Worksheet
Scheme of Work Link and Related Blogs
Angle Properties SoWGeometrical Reasoning in Key Stage 3 Blog
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