You ought to rely on the fact that the sum of the angles of quadrilaterial is equal to 360 degrees. Let x be the value of one angle, y be the one of the other, z - the 3rd and w - the 4th. We have the firrst equation x + y + z + w = 360. Taken separately x = y - 11, z = 2y, w = 1.5z. Got the system {x + y + z + w = 360, x = y - 11, z = 2y, w = 1.5z}. Let's solve it for any chosen variable, y for example. In terms of y w = 1.5*2y = 3y, z = 2y, x = y - 11. Inserting them into the 1st equation, y - 11 + y + 2y + 3y = 360 => 7y = 371 = > y = 53 (degrees). Inserting into the subsequent equations we find x = 53 - 11 = 42, z = 2*53 = 106, w = 3*53 = 159 degrees. As you could possibly notice the found values satisfy the requirement of the four angles to form an ascending sequance.
[input]solve(x + y + z + w = 360, x = y - 11, z = 2y, w = 1.5z, x,y,z,w)[/input]
+259 
