Step-by-step explanation:
the x and y-axis are always perpendicular to each other. Meaning that the angle between the x an y-axis is always 90 deg
the angle here shows that it starts on the x-axis in quadrant 1 and goes counterclockwise to the y-axis
since it doesnt go beyond the first quadrant, it means that it must be less than 90 deg
so it must be 80 deg
