Geometry & measures · Perimeter, area & volume
Chapter 1 · 3
The idea
Properties of shapes and solids (angles, triangles, quadrilaterals, symmetry, nets)
The words that pin a shape down exactly: the four types of angle and how to measure a length and an angle, triangles and the quadrilateral family by their sides, angles and diagonals, lines of symmetry and rotational symmetry, polygons up to ten sides, and solids with their faces, edges, vertices and nets.
A full journey — read it, play with it, work it, then earn real exam marks. Everything stays on the timeline below.
In this lesson — start anywhere
Geometry & measures · Perimeter, area & volume
Properties of shapes and solids (angles, triangles, quadrilaterals, symmetry, nets)
The words that pin a shape down exactly: the four types of angle and how to measure a length and an angle, triangles and the quadrilateral family by their sides, angles and diagonals, lines of symmetry and rotational symmetry, polygons up to ten sides, and solids with their faces, edges, vertices and nets.
Why it works
Angles: how far a corner turns
Try describing a shape over the phone so that a friend can draw it exactly. "A sort of diamond" will not do. Maths has a word for every feature, and this lesson builds them all from one square sheet of paper.Start with its corners. An angle measures turn. Each corner of the sheet is a quarter turn, a right angle of , marked with a small square. Every other angle is sized up against that corner.
Keep reading — free
The rest of the explanation, plus 4 worked examples you step through move by move.
Start freeTakes a minute — no card.