Question 255124
I assume it is isosceles. We can use Pythagorean theorem
a^2 + b^2 = c^2
and then
3^3 + 4^2 = c^2
9 + 16 = c^2
25 = c^2
5 = c. 
The perimeter is 3 + 4 + 5 + 5 = 17 m.