1 and 3 have the same angle and 2 and 4 have the same angle. Since we know what 1 is we know what 3 is, add them together then subtract that from 360 = 148. To figure out the angles of 2 and 4 divide 148 by 2 = 74. 1 and 3 are 106 degrees and 2 and 4 are 74 degrees :)