If XYZ above is equilateral, what is the value of r + s + t + u ?
Correct Answer: 300
Since XYZ is equilateral, r = u = 60. The sum of s + t equals 180 since the two angles form a straight line. Therefore, r + s + t + u = 60 + 60 + 180 = 300.
(from the October 14, 1997 test)