given that the circle radius of 6 cm and a minor arc ST = 11pi/2. the measure of the angle rst can be solve using the formula s = ra where s is the lenght of the minor arc r is the radius of the circle and a is the measure of the angle in radians s = ra a = s/r a = (11pi/2) / 6 a = 11pi/12 or a = 165 degrees is the measure of angle RST