What is the area of the sector bound by the center of the circle and arc cd in the circle below? radius equals 10 feet central angel is 40 degrees

A = (1/2) r^2 α                  (α must be in radians)
a = (1/2) r^2 α *(pi/180)    (to convert to radians)

a = (1/2) * 10^2 * 40 * (pi/180)
a = (100 pi) / 9 ft^2  EXACT answer
a = 34.89 ft^2  decimal approximmation

Answer d; a supplementary angle = 180°, so if that angle = 150°, y would = 30°.