a.
∠1 and ∠2 are supplementary angles, therefore:
------------------------------------------------
b.
∠5 and (∠3 + ∠4) are supplementary, so:
---------------------------------------------------
c. ∠4 can be found using the triangle sum theorem:
-------------------------------------------
d. ∠6 and (∠7 + ∠8) are supplementary, so:
-----------------------------------------------------------------
e.
∠7 can be found using the triangle sum theorem, so:
-----------------------------------
f. ∠9 and ∠10 are supplementary, so:
------------------------------------------------
g.
∠10 and (∠7 + ∠8) are corresponding angles, so: