To find the perimeter we need to find the lenght of each segment.
The vertexes of the figure are P(-3,0), Q(-5,3), R(0,3), S(3,5), T(5,2), U(2,0), V(5,-2), W(3,-5), X(0,-3) and Y(-5,-3).
We are going to use the formula:
Now, to simpligy things we notice from the figure (and it is confirmed by the points) that it is symmetric across the x-axis, so we won't need to find all the distances; we are only going to find d(P,Q), d(Q,R), d(R,S), d(S,T), d(T,U), so let's do that:
With this lengths we can find half of the perimeter, we add them to get:
Hence, the perimeter is: