Y = 140 degrees
A straight line is 180 degrees, so 40 degrees+ 25 degrees + X degrees= 180 degrees.
40+25=65, and 180-65=115. X=115 degrees
X, Z, and the 25 degree angle also makes a straight line.
115 degrees + 25 degrees + Z = 180 degrees
115+25=140, and 180-140=40, so Z=40 degrees
Z and Y also make a straight line
40 degrees + Y = 180 degrees, so Y=140 degrees
