Area of the triangle is expressed by the product of the base and the height divided by two. This is from the idea that a parallelogram having an area of length times width can be divided yielding to two triangles.
Area of shaded region = Area of triangle ABC - Area of triangle XBY
Area of triangle ABC = (6) (6) / 2 = 18 cm^2
Area of triangle XBY = (4) (4) / 2 = 8 cm^2
Area of shaded region = 18 - 8 = 10 cm^2