Question

An aquarium is in the form of a cuboid whose external measures are $80cm\times 30cm\times 40cm$. The base, side faces and back face are to be covered with a colored paper. Find the area of the paper needed.

Answer 1

We calculate the area total the aquarium $A_{tot}=2(ab+ah+bh)=2(80\times 30+80\times 40+30\times 40)$

$=2\times (2400+3200+1200)=136000c{m}^2$

$A_f=a\times h=80\times 40=3200c{m}^2$

$A_t=a\times b=80\times 30=2400c{m}^2$

$A=A_{tot}-(A_f+A_t)=136000-(2400+3200)$

$=8000c{m}^2$.