The length, breadth and height of a cuboidal room are in the ratio 20 : 12 : 9. If the area of four walls of room is 2304 cm2 then find the total surface area of a cube whose side length is equal to the height of cuboid.
The length, breadth and height of a cuboidal room are in the ratio 20 : 12 : 9. If the area of four walls of room is 2304 cm2 then find the total surface area of a cube whose side length is equal to the height of cuboid. Correct Answer 1944 cm<sup>2</sup>
Given:
The length, breadth and height of a cuboidal room are in the ratio 20 : 12 : 9
The area of four walls of room is 2304 cm2
Formula used:
Area of four walls of cuboid = 2 (l + b) × h
Total surface of cube = 6a2
Calculation:
Let the ratio be x
So, length of cuboid = 20x
Breath of cuboid = 12x
Height of cuboid = 9x
Since, Area of four walls of cuboid = 2 (l + b) × h
2304 = 2 (20x + 12x) × 9x
⇒ 576x2 = 2304
⇒ x2 = 4
So, x = + 2 or x = – 2 (not possible)
So, length = 20 × 2 = 40cm
Breadth = 12 × 2 = 24cm
And height = 9 × 2 = 18cm
According to question,
Side of cube = height of cuboid = 18cm
So, total surface area of cube = 6 × (18)2 cm2
Hence, 1944 cm2