Angle R =70°
Angle R is inscribed in this circle & its sides intercept the circle in Q & S
WE know that mes of inscribed circle = mes of the ARC intercepted &
divided by 2:
mes Angle R(=70°) = mes Arc QS/2 or (141x-1)/2
So (141x-1)/2 70 ==>141x-1 = 140 & x=1