1. **State the problem:** We need to find the area of the blue shaded region, which is the area of a right triangle minus the area of a circle inside it.
2. **Given:** The right triangle has legs of length 20 cm each.
The circle inside has a radius of 4 cm.
3. **Formula for the area of a right triangle:**
$$\text{Area}_{\triangle} = \frac{1}{2} \times \text{leg}_1 \times \text{leg}_2$$
4. **Calculate the area of the triangle:**
$$\text{Area}_{\triangle} = \frac{1}{2} \times 20 \times 20 = \frac{1}{2} \times 400 = 200 \text{ cm}^2$$
5. **Formula for the area of a circle:**
$$\text{Area}_{circle} = \pi r^2$$
6. **Calculate the area of the circle:**
$$\text{Area}_{circle} = \pi \times 4^2 = \pi \times 16 = 16\pi \text{ cm}^2$$
7. **Calculate the area of the blue shaded region:**
$$\text{Area}_{blue} = \text{Area}_{\triangle} - \text{Area}_{circle} = 200 - 16\pi$$
8. **Approximate the value using $\pi \approx 3.1416$:**
$$16 \times 3.1416 = 50.2656$$
$$\text{Area}_{blue} \approx 200 - 50.2656 = 149.7344 \text{ cm}^2$$
9. **Round to the nearest hundredth:**
$$149.73 \text{ cm}^2$$
**Final answer:** The area of the blue shaded region is approximately $149.73$ cm$^2$.
Triangle Circle Area C9916D
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