Question

An open rectangular cistern when measured from outside is 1.35 metre long 1.08 metre board and 90 cm It is made up of iron which is 2.5 cm find the capacity of the question and the volume of the iron used.​

Answer 1

The capacity of the cistern is
`1.2231~m^3`

The volume of iron used is
`0.0891~m^3`

Explanation:

Volume

The volume of a rectangular box of dimensions x,y,z is given by:

V = x.y.z

The external dimensions of the rectangular cistern are 1.35 m, 1.08 m, and 0.90 m, thus the external volume is:

`V_e=1.35*1.08*0.90=1.3122~m^3`

The cistern is made of iron 2.5 cm= 0.025 thick, thus the internal dimensions are:

1.35 - 0.025 = 1.325 m

1.08 - 0.025 = 1.055 m

0.90 - 0.025 = 0.875 m

The internal volume is:

`V_i=1.325*1.055*0.875`

`V_i=1.2231~m^3`

The capacity of the cistern is 1.2231~m^3

The volume of iron used is the difference between the external and the internal volumes:

`V_(iron)=1.3122~m^3-1.2231~m^3`

`V_(iron)=0.0891~m^3=89.1~lt`

The volume of iron used is
`0.0891~m^3`