Surface area and nets

The question
71310 cm²

Surface area of a 7 × 10 × 13 box

How it works.

7 × 10 × 13 cm
front and back:2 × 7 × 13 =182
front and back:2 × 7 × 13 =182
the two sides:2 × 10 × 13 =260
front and back:2 × 7 × 13 =182
the two sides:2 × 10 × 13 =260
top and bottom:2 × 7 × 10 =140
front and back:2 × 7 × 13 =182
the two sides:2 × 10 × 13 =260
top and bottom:2 × 7 × 10 =140
total:582
  1. 01

    A box has six faces, but the drawing shows only three. They come in three matching pairs.

  2. 02

    Front and back are 7 by 13, so that pair is 2 × 7 × 13 = 182.

  3. 03

    The two sides are 10 by 13, so that pair is 2 × 10 × 13 = 260.

  4. 04

    Top and bottom are 7 by 10, so that pair is 2 × 7 × 10 = 140.

  5. 05

    Add the three pairs: 182 + 260 + 140 = 582 square cm.