The area of a triangle is equal to the square of the radius divided by 2, so the square of the radius is equal to 15*2=30 cm2, the area of a circle is equal to 30*3. 14=94.2 cm2, and the area of this small sector is equal to 23.55 cm2. The area of the sector minus the area of the triangle is equal to the area of the shadow part, that is, 23.55-/kloc.