Surface area is the total area of all the faces of a solid. A net is the flat shape that folds up to make the solid. The net of a cuboid has six rectangles.
A cuboid has three pairs of equal faces: top and bottom, front and back, and the two sides. For a cuboid 4 cm by 3 cm by 2 cm, the faces are 4 × 3 = 12, 4 × 2 = 8 and 3 × 2 = 6. Double the total: 2 × (12 + 8 + 6) = 52 cm².
Worked example
Find the surface area of a cube with edges of 5 cm.
- Each face is 5 × 5 = 25 cm².
- A cube has 6 faces: 6 × 25 = 150.
Answer:150 cm²
Key words
- surface area
- the total area of all faces
- net
- a flat pattern that folds into a solid
- face
- a flat surface of a solid
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Common Core-referenced: 6.G.A.4