Answer
15.708
Work Step by Step
Given right triangle
$(3\sqrt 5)^{2}$ =$x^{2}$ + $2x^{2}$
45 = 5$x^{2}$
$x^{2}$ = $\frac{45}{5}$ = 9
x = 3
The perimeter of given triangle is
x + 2x+ 3$\sqrt 5$
Put the value of x
3+6+3$\sqrt 5$ = 9 + 3$\sqrt 5$ = 3(3+$\sqrt 5$) = 15.708