The three statements that are always true regarding the diagram are:
m∠3 + m∠4 + m∠5 = 180° (the sum of the angles in a straight line)
m∠5 + m∠6 = 180° (the sum of the angles in a straight line)
m∠2 + m∠3 = m∠6 (the exterior angle of a triangle is equal to the sum of its interior opposite angles)