Angle Geometry

Angle geometry in Year 8 is the angle chase: a chain of short steps, each one an equation with its reason. This NSW Year 8 maths subtopic (NESA outcome MA4‑ANG‑C‑01) builds on facts from Year 7, such as angles on a straight line adding to \(180^\circ\), angles at a point adding to \(360^\circ\) and vertically opposite angles being equal.

You will find complementary and supplementary angles, unknown angles where lines cross, and angles written as expressions such as \(x + 2x + (x + 14) = 180\). You will also use the fact that a triangle's angles add to \(180^\circ\), the equal base angles of an isosceles triangle, the exterior angle of a triangle and angle bisectors, and find the angle between an ironing board's legs and the floor. It is part of Year 8 Geometry.