Hello.

area of sector   =   (1/2) * (radius)² * measure of central angle in radians

area of sector   =   (1/2) * 12² * 2.3      sq. meters

area of sector   =   (1/2) * 144 * 2.3      sq. meters

area of sector   =   72 * 2.3     sq meters

area of sector   =   165.6        sq meters

I think I see what you did......remember  12² = 12 * 12   ....NOT....  12 * 2