nomor 4 beserta caranya ,pls besok dikumpulin

a.
BAD = 180 - (100+60)
BAD = 180 - 160
BAD = 20

b.
ADB = 180 - 80
ADB = 100

c.
BAD + ABD + DBC + BCA = 180
20 + 60 + DBC + 60 = 180
DBC = 180 - 140
DBC = 40

ABC = ABD + DBC
ABC = 60 + 40
ABC = 100

d.
CBD = DBC
CBD = 40

e.
BDC = 180 - ADB
BDC = 180 - 100
BDC = 80