1. Prove Area of [HBK] (blue) = Area of [CBK] (red).
2. Prove Area of [CBL] (green) = Area of [ABK] (yellow).
3. Prove Area of [CBK] (red) = Area of [ABK] (yellow) and thus Area of [CBL] (green) = Area of [HBK] (blue).
4. Therefore, area of the brown rectangle is . By similar construction, the area of the black rectangle is found to be .
5. What is your conclusion?