Question

18.) The dimensions of a cuboid are in the ratio 4:2:1 and the total surface area is
2800 m2. Find its volume.

19. A cuboidal metal block of dimensions 2 m x 1m x 1 m weighs 400 kg. Find the
1 1
weight of the block of the same metal of size 1 m x
2 2
m X-
m.

20. If 1 cm of wood weighs g, find the weight of a wooden block whose length is
2
10 cm, breadth is 5 cm and height is 3 cm.​

Answer 1

Answer:

Let the dimensions be 4x,2x and x

Therfore, TSA of cuboid=

2(lb+bh+lh)

or 2(4x*2x+2x*x+x*4x)

or 2(8x²+2x²+4x²)

or 2(14x²)

or 28x²

But TSA=2800(Given)

So on comparing,

28x²=2800

or x²=100

or x=10

Therefore

l=40m

b=20m

h=10m

So volume=

length*breadth*height

or 40*20*10

or 8000m³