Introducing Angles in a Triangle

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°.
View online lesson
Lesson Downloads
Download PowerPoint Download Notebook Download Flipchart Download Worksheet
Scheme of Work Link
Angle Properties
Related Blog
Geometrical Reasoning in Key Stage 3
IMMEDIATE DOWNLOAD

Mr Mathematics Blog

Mathematics OFSTED Inspection – The Deep Dive

Earlier this week, my school took part in a trial OFSTED inspection as part of getting ready for the new inspection framework in September 2019. This involved three Lead Inspectors visiting our school over the course of two days. The first day involved a ‘deep dive’ by each of the Lead Inspectors into Mathematics, English […]

How to Solve Quadratics by Factorising

The method of how to solve quadratics by factorising is now part of the foundational knowledge students aiming for higher exam grades are expected to have.   Here is an example of such a question. Solve x2 + 7x – 18 = 0 In my experience of teaching and marking exam papers students often struggle with […]

How Write 3 Part Ratios

When learning how to write 3-part ratios students need to understand how ratios can be made equivalent. The start of the lesson reminds students by asking which of six ratios is the odd one out.  This is presented to the class as they come into the lesson.    Writing Equivalent Ratios  A few students immediately go […]