The approximate volume of a cube of side a meters on increasing the side by 4% is:

$1.04a^3\,m^3$ $1.004a^3\,m^3$ $1.12a^3\,m^3$ $1.12a^2\,m^3$

$1.12a^3\,m^3$

x = side of cube so volume = $V(x) = x^3$ $x=a$ $\frac{dV(x)}{dx}=3x^2$ now $x = a +4\%a=1.04a$ $V(x+dx)=V(x)+\frac{d(V(x))}{dx}×Δx$ $Δx=\frac{4a}{100}$ $⇒a^3+3a^2×\frac{4a}{100}$ $=\frac{112}{100}a^3m^3=1.12a^3\,m^3$