Hey there!
As we see for ∠4, the number's that contribute to this are angels ∠3 and angel ∠1.
Know, we would have to check what is also equivalent to 4.
As we look around this figure, we see how ∠3 and ∠2 are equivalent to ∠4.
Your correct answer to this question would be . . .
[tex] \left[\begin{array}{ccc}\boxed{\boxed{m2+m3}}\\ this \ would \ be \ your \ answer\end{array}\right] [/tex]
Hope this helps you!
~Jurgen