The commutative property of addition states that you can change the order of addends in a sum. The associative property of addit
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Answer:
Step-by-step explanation:
a + 143 = 180 {Linear pair}
a = 180 - 143
a = 37
37 + 93 + b = 180 {Angle sum property of triangle}
130 + b = 180
b = 180 - 130
b = 40
c + b = 90
c + 40 = 90
c = 90 - 40
c = 50
d + 120 = 180 {Linear pair}
d = 180 - 120
d = 60
? = 60 + 40 {Exterior angle property of triangle}
? = 100
