1. **State the problem:** We need to find the area of the blue shaded region inside a large rectangle of height 20 cm and width 10 cm, where a right triangle with one leg 8 cm is formed inside, dividing the rectangle into two blue regions. 2. **Understand the figure:** The rectangle has dimensions 10 cm (width) and 20 cm (height). 3. **Identify the triangle:** The triangle is right-angled with one leg along the vertical side measuring 8 cm. 4. **Calculate the area of the triangle:** The base of the triangle is the width of the rectangle, 10 cm, and the height is 8 cm. $$\text{Area of triangle} = \frac{1}{2} \times \text{base} \times \text{height} = \frac{1}{2} \times 10 \times 8 = 40\text{ cm}^2$$ 5. **Calculate the area of the rectangle:** $$\text{Area of rectangle} = \text{width} \times \text{height} = 10 \times 20 = 200\text{ cm}^2$$ 6. **Calculate the area of the blue shaded region:** The blue shaded region consists of the triangle above the hypotenuse and the rectangle below it. Since the hypotenuse divides the rectangle into two blue regions, the total blue area is the entire rectangle minus the non-blue triangle area (if any). But from the description, both regions are blue, so the total blue area is the entire rectangle. 7. **Conclusion:** The blue shaded region covers the entire rectangle, so its area is: $$200\text{ cm}^2$$