demonstrate that the interior angle sum of a triangle in the plane is 180° and apply this to determine the interior angle sum of other shapes and the size of unknown angles

How Bloomi helps with this

This is a NAPLAN-year topic. Bloomi teaches it with a short explainer, guided practice, and NAPLAN-style questions — every one traceable to this exact code.

What this looks like in the classroom

• using concrete materials to demonstrate that the sum of the interior angles of a triangle is 180°; for example, using paper triangles and tearing to demonstrate that the interior angles when combined form \(180\)°
• using decomposition and the angle sum of a triangle to generalise the interior angle sum of an \(n\)-sided polygon, as \(180(n-2)\;=\;180n-360\)