Think of definition of obtuse angles.

Think of the base or reference line.

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

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

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

Take base or reference line first.

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

What do you understand by right angle?

Think of the word Obtuse.

Think of definition of acute angles.