Complementary and Supplementary Angles

Two angles are complementary when they add to \(90^\circ\) and supplementary when they add to \(180^\circ\). This NSW Year 7 maths subtopic (NESA outcome MA4‑ANG‑C‑01) uses these facts to find unknown angles inside a right angle or on a straight line.

You will find the complement of \(35^\circ\) (\(55^\circ\)) and the supplement of \(70^\circ\) (\(110^\circ\)), write a reason before each equation, and solve for pronumerals in diagrams of adjacent angles. Some questions are puzzles, such as an angle that is \(36^\circ\) smaller than its complement. The corner of a picture frame, split by a diagonal brace, is a real example. This subtopic is part of Year 7 Angles.