In square ABCB, the side length is 1cm, EF is the midpoint of BC and CD respectively, calculate the area of shadow part! Trouble,

In square ABCB, the side length is 1cm, EF is the midpoint of BC and CD respectively, calculate the area of shadow part! Trouble,

My estimation is to find the area of the triangle EFC, connect BD, connect AC, AC intersects EF at g, CG is perpendicular to EF, first find the side length of BD as 2 under the root, in the isosceles triangle BCD, the isosceles EF = BD / 2, then CG = AC / 4, so that we can know the bottom and height of the ECF, and then we can find the area. If the shadow is another block, we can get the area by subtracting the area above from the square area