Question 1190944
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Answer: 60 degrees


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Reasoning:


Complementary angles add to 90 degrees by definition.
<font color=red><u>Co</u></font>mplementary angles form a <font color=red><u>co</u></font>rner. 
Both "complementary" and "corner" start with "Co", and this is the trick you can use to remember the definition.

 
In contrast, supplementary angles add to 180 degrees
The angles form a straight line.
"supplementary" and "straight" both start with S.


Anyways, the angles S and Y add to 90 degrees, which means,
(angle S) + (angle Y) = 90
(3Y-150) + (Y) = 90
4Y - 150 = 90
4Y = 90+150
4Y = 240
Y = 240/4
Y = 60
Angle Y is 60 degrees


From there, we can find angle S if you wanted
S = 3Y - 150
S = 3*60 - 150
S = 180 - 150
S = 30


As a way to check,
(angle S) + (angle Y) = 60 + 30 = 90
The answer is confirmed.
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