Answer:
178
Explanation:
All right!!
Line l is parellel to line m.
So if r is 91 then we can infer that s helps it make a 180 degree angle/straight line.
So 180 - 91 = 89
s = 89
If the two lines are parallel then s = u because of inner angles/outer angles stuff.
If s=u then u = 89 as well.
And because of vertical angles, t =u so t = 89.
Now the question asks to find t + u, so t + u = 89 + 89 = 178
Hope that helps!!