Using the pythagoras theorem
r^2 = 12^2 + (18-r)^2
r^2 = 144 + 324 - 36r + r^2
36r = 144 + 324 = 468
r = 468 / 36 = 13 cm Answer
sin 1/2 < AOB = 12 /13
1/2 < AOB = 67.38
< AOB = 134.8 Answer
Area of major sector OAPB
ARea of the circle = pi r^2 = 144pi
so area of mafor sector OAPB = (225/2 / 360) * 144pi = 90.08 pi or
283 cm^2 to nearest whole number
