Question 738135
Set up two equations.<P>
1:  Angle x is two times angle y:  x=2y<P>
2:  The sum of all angles is 180 degrees: 72 + x + y = 180 so x+y = 180-72 = 108<P>
Substitute 2y for x (as shown in equation 1) in equation 2.  2y+y = 108<P>
3y = 108<P>
y = 36<P>
x = 2y = 2(36) = 72 degrees.  You had it backwards...x is twice angle y.
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