[düng Jiáo]

Vertical diagonal

Vertical angle (diagonal) means that if two sides of one angle are opposite extension lines of two sides of another angle, and the two angles have the same vertex, then the two angles are diagonal. The diagonal range is between 0 degree and 180 degree, excluding 0 degree and 180 degree. The antipodal angle is two angles with special position, and the equality of antipodal angle reflects the relationship between the two angles.