+142 Suppose that in a certain triangle, the degree measures of the exterior angles are in the ratio \(2:3:4\)
If the largest interior angle measures \(y^\circ\), what is the value of \(y\)?
+142 Given that the three angles are in the ratio, \(2:3:4\) we can write them as \(2a^\circ\), \(3a^\circ\), and \(4a^\circ\) for some number \(a\).
The sum of the interior angles of any triangle is \(180^\circ\), so we have
\(2a+3a+4a = 180\)
We can write this equation as \(9a=180\)and solve to get \(a=20\). Thus the measures of the three angles are \(2\cdot 20=40\) degrees, \( 3\cdot 20=60\)degrees, and \(4\cdot 20=80\) degrees. In particular, if the largest angle is \(y^\circ\), then \(x=\boxed{80}\).
That's what I got and when I put it in it was correct.
Edited: Ok I see what you did. You did the exterior angles but the problem asked for the interior angles. 
+129852 Let's look at this again
The exterior angles sum to 360
The smallest exterior angle will be supplemental to the largest interior angle
So....the smallestt exterior angle is (2/9)(360) = 80°
So...the largest interior angle = 180 - 80 = 100° = y
EDIT TO CORRECT AN ERROR
