An investor puts $31\mathrm{.}00\%$ of his investment into Cisco Systems, and the remaining $69\mathrm{.}00\%$ into Apple Computer. The standard deviation on Cisco Systems stock is $39\mathrm{.}00\%,$ while the standard deviation on Apple Computer is $27\mathrm{.}00\%.$ Find the standard deviation of this portfolio if the correlation between the two stocks is $0\mathrm{.}66.$

Answer format: Percentage Round to: $2$ decimal places $($Example: $9\mathrm{.}24\%,\%$ sign required. Will accept decimal format rounded to $4$ decimal places $($ex: $0\mathrm{.}0924))$