Question

the surface area of a cuboid is 1300 CM square if its breadth is 10 cm and height is 20 cm find the length

Answer 1

Let length be l
Breadth, b = 10
Height, h = 20
$surface \: \: area = 2(lb + bh + lh) \\ 10l + 10 \times 20 + 20l = \frac{1300}{2} = 650 \\ 30l = 650 - 200 = 450 \\ l = 15 \: cm$

Answer 2

The length of the cuboid is 15 cm.

• Let the length of the cuboid be l cm.

Breadth of the cuboid is 10 cm

Height of the cuboid is 20 cm.

Total surface area of the cuboid is 1300 cm²

• Formula to find the surface area of the cuboid is 2(lb + bh + hl).

1300 = 2 (10l + 200 + 20l)

650 = 30l + 200

450 = 30l

l = 15 cm