Answer:
The capacity of the cistern is [tex]1.2231~m^3[/tex]
The volume of iron used is [tex]0.0891~m^3[/tex]
Step-by-step 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:
[tex]V_e=1.35*1.08*0.90=1.3122~m^3[/tex]
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:
[tex]V_i=1.325*1.055*0.875[/tex]
[tex]V_i=1.2231~m^3[/tex]
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:
[tex]V_{iron}=1.3122~m^3-1.2231~m^3[/tex]
[tex]V_{iron}=0.0891~m^3=89.1~lt[/tex]
The volume of iron used is [tex]0.0891~m^3[/tex]