Answer:
x = 35°
Step-by-step explanation:
The three angles in a triangle add up to 180°.
The little square in the corner of one angle means that is a right angle and is 90°.
90° + 55° + x = 180°
145° + x = 180°
Subtract 145° from both sides.
x = 180° - 145°
x = 35°
