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The surface area of a cuboid is 1300 cm2. If its breadth is 10 cm and height is 20 cm2, find its length.

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Question

The surface area of a cuboid is 1300 cm2. If its breadth is 10 cm and height is 20 cm2, find its length.

Short/Brief Note
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Solution

Let, l → Length of the cuboid

Breadth of the cuboid (b) = 10 cm

Height of the cuboid (h) = 20 cm

Surface area of the cuboid (A) = 1300 cm2

We have to find the length of the cuboid

We know that,

     A = 2 (lb + bh + hl)

1300 = 2(10l + 10 × 20 + 20l)

1300 = 2 (200 + 30l)

1300 = 400 + 60l

l =`(1300-400)/60`

 `=900/60`

  = 15 cm 

Length of the cuboid is 15 cm  .

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Chapter 18: Surface Areas and Volume of a Cuboid and Cube - Exercise 18.3 [Page 35]

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RD Sharma Mathematics [English] Class 9
Chapter 18 Surface Areas and Volume of a Cuboid and Cube
Exercise 18.3 | Q 7 | Page 35

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