Shaded Area 1E2D5C
1. **Problem 1: Area of the ring-shaped shaded part**
We have two circles: a large circle with radius $6$ m and a smaller inner circle with radius $4.1$ m. The shaded area is the area of the large circle minus the area of the smaller circle.
Formula for the area of a circle: $$A = \pi r^2$$
Calculate the areas:
- Large circle area: $$\pi \times 6^2 = 36\pi$$
- Small circle area: $$\pi \times 4.1^2 = 16.81\pi$$
Shaded area: $$36\pi - 16.81\pi = (36 - 16.81)\pi = 19.19\pi$$
Approximate using $\pi \approx 3.1416$:
$$19.19 \times 3.1416 = 60.28$$
2. **Problem 2: Area of the semicircle with diameter 9 m**
Radius $r = \frac{9}{2} = 4.5$ m.
Area of full circle: $$\pi r^2 = \pi \times 4.5^2 = 20.25\pi$$
Area of semicircle: $$\frac{1}{2} \times 20.25\pi = 10.125\pi$$
Approximate:
$$10.125 \times 3.1416 = 31.80$$
3. **Problem 3: Area of the rectangle with two semicircular cutouts**
Rectangle area: $$9 \times 5.6 = 50.4$$
Each semicircle has diameter $5.6$ m, so radius $r = \frac{5.6}{2} = 2.8$ m.
Area of one semicircle: $$\frac{1}{2} \pi r^2 = \frac{1}{2} \pi \times 2.8^2 = \frac{1}{2} \pi \times 7.84 = 3.92\pi$$
Two semicircles area: $$2 \times 3.92\pi = 7.84\pi$$
Approximate:
$$7.84 \times 3.1416 = 24.63$$
Shaded area = rectangle area minus cutouts:
$$50.4 - 24.63 = 25.77$$
**Final answers:**
1. $60.28$ m²
2. $31.80$ m²
3. $25.77$ m²