Let R be the circle centred at (0, 0) with radius 10. The lines x = 6 and y = 5 divide R into four regions R1, R2, R3, andR4. Let [Ri] denote the area of region Ri. If [R1] > [R2] > [R3] > [R4], then find [R1] - [R2] - [R3] + [R4].
[R1] - [R2] - [R3] + [R4] = 150.
+34 
