The intercepted arc of the angle labeled 1 is composed of two arcs measuring 220° and 60°. Together, these arcs sum to 220° + 60° = 280°.
Step 2: Calculate the measure of angle 1
The measure of an angle formed by two tangents to a circle is half the difference between the measures of the intercepted arcs. The circle's total arc measure is 360°. The angle labeled 1 intercepts an arc measuring 280°. The other intercepted arc measures 360° - 280° = 80°. Therefore, the measure of angle 1 is (280° - 80°)/2 = 200°/2 = 100°, or (360° - 280° + 80°)/2 = 160°/2 = 80°. There appears to be a typo in the problem or its solution choices. Given the diagram, the correct answer should be 80°.