The formula for circumference: C = pi · diameter.
C = pi · 28 feet
C = 87.965 feet
Since PS is a diameter, arc(ST) = 180o - 125o = 55o
So, arc(ST), in feet, will be (55/360) · 87.965 feet = 13.4 feet
Arc(RPT) = 360o - arc(RS) - arc(ST) = 360o - 97o - 55o = 208o
Arc(RPT, in feet, will be (208/360) · 87.965 feet = .........