74 degrees, because angle 1 and 8 add up to 73 degrees, so to make 180 you subtract 180-73 degrees, which makes 112 degrees for angle 9. Angle 9 and 12 are supplementary so they should both add up to 180. That means that angle 12 must be 68. Angles 12, 7, and 6 must add up to 180, so 38+68=106. 180-106=74. Therefore, angle 6 is 74 degrees