Cube nets and surface area

A cube has six square faces; any valid net must fold without overlap to make exactly those six faces.

Key formulas

Edge a → each face a² → total 6a². The hard part in exams is recognising whether a drawn net can actually form a cube.

A straight row of six squares folds into a tube, not a cube. More than four squares in a row also fails.

a = 4 cm → surface area = 96 cm². Paint questions often ask how many faces get painted — that is surface thinking, not volume.

Problem. A cube has edge 5 cm. Find its total surface area.

Solution. Surface area = 6a² = 6 × 25 = 150 cm².

A 3×3×3 cube of unit cubes: only the outer faces are painted.

Cube edge 7 cm. Surface area is:

Eleven hexomino nets fold into a cube.