One of the triangles (that on the left, top) has 2 equal sides, and thus is isosceles. The angle immediately adjacent to and to the right of 110 degrees is 180-110 degrees, or 70 degrees, which means that angle 1 is also 70 degrees. The remaining angle is 180 degrees less 2(70 degrees), or 40 degrees; thus, angle 2, immediately adjacent to and to the right of this 40 degree angle, is 180-40, or 140 degrees. The triangle to the right and below the horiz. line has angle 40 degrees (using the principle of vertical angles); thus, angle 3 is 180-(40+90) degrees, or 50 degrees.
