Question

If the length of a rectangular parallelepiped is 3 times of its breadth and 5 times of its height and its volume is 144400 cu.cm, then area of the total surface will be

Answer 1

Given:

The length of a rectangular parallelepiped is 3 times of its breadth and 5 times of its height and its volume is 144400 cu.cm,  

To find:

The area of the total surface will be

Solution:

From given, we have,

l=3b=5h

so, b=l/3 and h=l5

The volume of cuboid = l × b × h = l × l × l/(3 × 5) in this case

14440 = l³/15 => l³ = 15 × 14440 = 216600

⇒ l = ∛216600 = 60.0555cm ≈ 60 cm

length = 60 cm

width = l/3 = 60/3 = 20 cm

height = l/5 = 60/5 = 12 cm

Total area of cuboid = 2(l × b + b × h + h × l)

= 2(60 × 20 + 20 × 12 + 12 × 60)

= 4320 sq cm.

Answer 2

Answer:

4320cm^3 is the correct information