Help help ​

volume of candle   =   $\frac13\pi r^2h$          Since  h = r , we can replace  h  with  r .

volume of candle   =   $\frac13\pi r^2r$

volume of candle   =   $\frac13\pi r^3$

surface area of candle   =   $\pi r^2+\pi r\sqrt{r^2+h^2}$        Since  h = r , we can replace  h  with  r .

surface area of candle   =   $\pi r^2+\pi r\sqrt{r^2+r^2}$

surface area of candle   =   $\pi r^2+\pi r\sqrt{2r^2}$

surface area of candle   =   $\pi r^2+\pi r\cdot r\sqrt{2}$

surface area of candle   =   $\pi r^2+\pi r^2\sqrt{2}$

ratio of the volume of candle to its surface area  =   $\frac{\text{volume of candle}}{\text{surface area of candle}}$

$\frac{\text{volume of candle}}{\text{surface area of candle}}\,=\,\frac{\frac13\pi r^3}{\pi r^2+\pi r^2\sqrt2}\\~\\ =\,\frac{\frac13r^3}{r^2+r^2\sqrt2} \\~\\ =\,\frac{\frac13r}{1+\sqrt2} \\~\\ =\,\frac{r}{3(1+\sqrt2)} \\~\\ =\,\frac{r(1-\sqrt2)}{3(1+\sqrt2)(1-\sqrt2)} \\~\\ =\,\frac{r(1-\sqrt2)}{3(1-2)} \\~\\ =\,\frac{r(1-\sqrt2)}{-3}$

Nice, hectictar   !!!!

Didn't know that you were fluent in Spanish!!!!....LOL!!!!