Classifying Triangles

Every triangle can be named in two ways: by its sides (equilateral, isosceles or scalene) and by its largest angle (acute, right or obtuse). This NSW Year 7 maths subtopic (NESA outcome MA4‑GEO‑C‑01) teaches you to read a diagram and classify a triangle correctly.

You will read tick marks and right-angle marks, name a triangle as \(\triangle ABC\), use equal base angles in an isosceles triangle to find unknown angles, decide which triangles cannot be drawn, and find a missing side from a perimeter. Roof trusses and shade sails are everyday triangles. It is part of Year 7 Geometry.