The measure of an inscribed angle is half of the measure of its intercepted arc. If given an intercepted arc given in terms of a variable (for example, part of the arc's measure is given with a variable x), set the measure of the inscribed angle equal to the expression of the entire arc divided by 2. It is then possible to solve for x. Also recall that the total measure of the arcs of a circle is 360°. Therefore, if the measure of an inscribed angle is unknown and its intercepted arc is not given, subtract the known arc measures from 360°. The inscribed angle of the unknown arc is half of this value.