What do you understand by right angle?

Think of definition of obtuse angles.

Take base or reference line first.

Think of the base or reference line.

First take the base line or reference line of the angle.

Distance between all points on two parallel lines is always same.

First take the base line or reference line of the angle.

Think of the word Obtuse.

First take the base line or reference line of the angle.

Think of definition of acute angles.