Answer:
Opposite sides are equal, which means that the given lengths are doubled and that'll have to equal a total of 82.
(2n) + (2n) + (4n + 5) + (4n + 5) = 82
Combine like terms;
4n + 8n + 10 = 82
12n + 10 = 82
Get rid of constants:;
-10 -10
12n = 72
Isolate n by getting rid of it's coefficient;
/12 /12
n = 6