Question 499347
a = first angle
.
b = second angle
b = a+10 (given)
or
a = b-10
.
c = third angle
c = 2b - 30
.
a + b + c = 180 (because it's a triangle)
.
substitute
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(b-10) + b + (2b-30) = 180
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b -10 +b +2b -30 = 180
4b -40 = 180
4b = 220
b = 55
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a = b-10
a = 45
.
Therefore,
c = 180 - (55+45)
c = 80
.
Check:
2b - 30 = 2(55) - 30
 = 110 - 30
 = 80
True.
.
Answer:
The three angles are 45, 55, and 80 degrees.
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Done.