Answer:
A) 3a = 180°
B) a+ 55° + 36° = 180°
C) x + y + z = 180°
Explanation:
The answer is the A option since all the side of the triangle could be the same, making it an equilateral triangle. ( 60° + 60° + 60° = 180° )
The sum means that all the angles are added, not necessarily being similar terms, which equals to 180°.
The terms don't have to be similar, for instance the B option,
a+ 55° + 36° = 180°
since you could find the value of a.
The same thing goes for C.
(Extra)
It is not D since x is multiplied with 3, not giving the sum.
It is not E since all the 3 terms are multiplied, not giving the sum.