Question 1196065
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A = first angle
B = second angle
C = third angle


We're given that <font color=blue>The third angle is fifteen more than the second</font>, which means C = B+15


Also, <font color=blue>The sum of the measures of the second and third angles is three times the measure of the first angle</font> which means:
B+C = 3A


We'll use the fact that for any triangle, the interior angles sum to 180
A+B+C = 180
A+(B+C) = 180
A+(3A) = 180
4A = 180
A = 180/4
A = 45


So,
B+C = 3A
B+C = 3*45
B+C = 135


Now plug in C = B+15 and solve for B
B+C = 135
B+B+15 = 135
2B+15 = 135
2B = 135-15
2B = 120
B = 120/2
B = 60


Then we can find C
C = B+15
C = 60+15
C = 75


<font color=red>Summary:</font>
A = 45 degrees
B = 60 degrees
C = 75 degrees
where A,B,C are the 1st,2nd,3rd angles in that exact order.
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