Finding the surface area of similar figures

I guess you mean surface area.

Let V₁ and V₂ be the volumes of the similar figures respectively.

Let A₁ and A₂ be the surface areas of the similar figures respectively.

$\frac{V_1}{V_2}=(scale\space factor)^3=(\frac{length\space of\space a\space side\space of\space V_1}{length\space of\space a\space side\space of\space V_2})^3$

$\frac{A_1}{A_2}=(scale\space factor)^2=(\frac{length\space of\space a\space side\space of\space V_1}{length\space of\space a\space side\space of\space V_2})^2$

$\therefore (\frac{V_1}{V_2})^2 = (\frac{A_1}{A_2})^3$