The perimeter of this shape is actually the same of a rectangle with sides 19 and 10.
See the attached picture: the perimeter of our shape is
[tex]AB+BC+CD+DE+EF+FA[/tex]
Whereas the perimeter of the outer rectangle would be
[tex]AB+BC+CD+DG+GF+FA[/tex]
So, as you can see, the only difference is that the first equation features [tex]DE+EF[/tex], while the other features [tex]DG+GF[/tex]. This is not a problem, because [tex]EDGF[/tex] is a rectangle, and thus we have [tex]ED=GF[/tex] and [tex]EF=DG[/tex].
So, the two perimeters are actually the same:
[tex]2(10+19)=2\cdot 29=58[/tex]
