 Example:
The length, width and height of a cuboid are 10 metres, 8 metres and 7 metres respectively. Find the lateral surface area of the cuboid.
Solution:
Given that,
l = 10 metres, b = 8 metres and h = 7 metres
Equation for lateral surface area = 2h (l+b).
Substituting the values of l, b and h we get,
= 2 * 7 (10 + 8)
= 14 * 18
= 252 square metres.
 Example:
The width and height of a cuboid are 6 metres and 4 metres respectively. Find the length if the lateral surface area of the cuboid is given by 300 square metres.
Solution:
Given that,
b = 6 metres and h = 4 metres
Equation for lateral surface area = 2h (l+b).
Substituting the values of b and h we get,
= 2 * 4 (l + 6)
Therefore 8 * (l + 6) = 300
i.e 8l + 48 = 300
i.e 8l = 300  48 = 252
i.e l = 252 / 8
Therefore l = 31.5
Hence length of the cuboid is 31.5 metres.
Directions: Read the above example carefully and answer the following questions:
 The length of a cuboid is 5 more than the width and 3 less than the height. If the lateral surface area is given by 256 square metres, then find its length, width and height.
 The length, width and height of a cuboid is given by x, 3x and 5x. Then find the lateral surface area. Also find the area when x = 10 metres.
