Answer:
x = 121°
Explanation:
The lower left vertex and 115 are adjacent and supplementary, thus
left vertex = 180° - 115° = 65°
The angle round a point = 360°, so the top vertex is
360° - 304° = 56°
The external angle of a triangle is equal to the sum of the 2 opposite interior angles.
x is an exterior angle of the triangle, thus
x = 65° + 56° = 121°