For #2, you could probably state that the pairs of angles are on a straight line.
#3: If two angles form a linear pair, then they are supplementary.
#4: Supplementary angles add to 180°.
#5: Transitive property of equality.
#6: Subtraction postulate.
#7: Congruent angles have equal measure.
#8:
Since B is the midpoint of AC, AB is congruent to CB.
Assuming BD⊥AC, we know that ∠ABD and ∠CBD are right angles and therefore are congruent.
BD is congruent to itself.
So by SAS, triangle ABD is congruent to triangle CBD.
#9:
SM and PD both cut across a 1×5 rectangle, so SM = PD.
MJ and DW both cut across a 1×2 rectangle, so MJ = DW.
JS and WP both cut across a 1×4 rectangle, so JS = WP.
By SSS, the triangles are congruent.
