Using the inscribed angle theorem, the measure of angle 4 in the diagram given is: m∠4 = 1/2 • m(SR) [option B].
How to find the missing angle using the inscribed angle theorem?
Based on the inscribed angle theorem, if we are given a circle that has an inscribed angle that is subtended by an arc, the arc measure is twice the measure of the inscribed angle, in order words:
inscribed angle measure = 1/2 * the measure of the arc.
Angle 4 in the circle shown is an inscribed angle
Arc SR is a subtended arc
Therefore, based on the inscribed angle theorem, we have:
m∠4 = 1/2 • m(SR) [option B].