Answer:
arc FS = 84°
Explanation:
the inscribed angle QRF is half the measure of its intercepted arc QF , then
arc QF = 2 × 48° = 96°
the sum of the arcs on a semicircle = 180° , that is
QF + FS = 180°
96° + FS = 180° ( subtract 96° from both sides )
FS = 84°