1.1 Understanding properties of:
isosceles triangle
equilateral triangle
right-angled triangle
Student to use terms such as ‘acute-angled triangle’, ‘obtuse-angle triangle’, ’right-angled triangle’, ‘isosceles triangle’ and ‘equilateral triangle’ to describe the triangles.
1.2 Sum of angles in a Triangle
Students able to state that the sum of angles in any triangle is 180°.
1.3 Finding unknown angles without additional construction of lines
Students able to:
- identify and justify the angle properties of triangles, e.g. fold an isosceles triangle cutout to show that the base angles are equal
- draw special triangles on square grid.
- use the angle properties of triangles to find unknown angles and explain how they obtain the answers
- sketch and draw different triangles according to given angles and lengths using ruler, protractor and set squares
Sum of Interior Angles of a Triangle
Refer this webpage for more fun facts about angles in a triangle