15) ∠BCD = 1/2 short arc BC = (360° -260°)/2 = 50° (C)
16) ∠K is supplementary to short arc JL = 180° -120° = 60° (C)
17) ∠V is half the difference of long arc TW and short arc UW.
.. (198° - UW)/2 = 69°
.. 198° -138° = UW = 60° (C)
18) ∠L is supplementary to short arc KM
.. KM = 180° -66° = 114° (C)
