One minor change will make it work.
T = 180:1:360;
k = .8823-((T-179)*(.0039));
s = 1.1e-2;
r = s*(T.^4);
r2 = k.*s.*(T.^4); % Or r2 = k.*(s*(T.^4)); Or r2=(k*s).*(T.^4);
plot(T,r,'-k',T,r2)
In general, whenever you have two or more vectors and you want their product to be a vector, use element-by-element multiplication (include the dot). Look at a small example:
a = 1:3
b = 5:7
a.*b
The same goes for division and exponentiation.
