A circle is shown. 2 secants intersect outside of the circle to form angle 1. The measure of the first arc formed is b degrees, and the angle of the second arc is a degrees. Arc c degrees is outside of the secants. Which formula would be used to find the measure of angle 1? One-half(a° + b°). One-half(a° – c°). One-half(b° + c°). One-half(a° – b°).