**Learning Intention: **“Demonstrate that the angle sum of a triangle is 180° and use this to find the angle sum of a quadrilateral.”

**Success Criteria: **Students will draw 2 copies of each of the triangles (acute, right-angled, obtuse, equilateral, isoceles and scalene) and show how, when the corners are removed, they can be placed on a straight line to form 180 degrees. This demonstrates that the sum of angles in a triangle is always 180 degrees.

This term we have started a new unit of work, learning how to estimate and measure angles. We have also identified and named triangles according to their side length and angles. Make sure you can identify and draw each of the following:

- equilateral triangle (three equal angles)
- isoceles triangle (two equal side and two equal angles)
- scalene triangle (three different angles and three different side lengths)
- acute angled triangle (all angles less than 90 degrees)
- right angled triangle (one angle of 90 degrees exactly)
- obtuse angled triangle (one angle greater than 90 degrees)

Remember that all the angles in a triangle always add to 180 degrees. The following links are to some interactive activities to investigate angles:

What’s my angle? from Ambleside Primary School.

Angle Activities from Ambleside Primary School.

Guess the angle from Crickweb.