Find the volume and surface area of a shpere of radius 3.5 cm.

Answer

To find the volume and surface area of a sphere with a radius of 3.5 cm, we will use the following formulas:

1. **Volume of a sphere**:
\[ V = \frac{4}{3} \pi r^3 \]
2. **Surface area of a sphere**:
\[ A = 4 \pi r^2 \]

### Step 1: Calculate the Volume

1. **Substitute the radius into the volume formula**:
\[ V = \frac{4}{3} \pi (3.5)^3 \]

2. **Calculate \( (3.5)^3 \)**:
\[ (3.5)^3 = 3.5 \times 3.5 \times 3.5 = 42.875 \]

3. **Substitute \(\pi\) with \(\frac{22}{7}\)**:
\[ V = \frac{4}{3} \times \frac{22}{7} \times 42.875 \]

4. **Calculate \( \frac{4 \times 22 \times 42.875}{3 \times 7} \)**:
\[ V = \frac{88 \times 42.875}{21} \]

5. **Calculate \( 88 \times 42.875 \)**:
\[ 88 \times 42.875 = 3775 \]

6. **Divide by 21**:
\[ V = \frac{3775}{21} \approx 179.76 \text{ cm}^3 \]

### Step 2: Calculate the Surface Area

1. **Substitute the radius into the surface area formula**:
\[ A = 4 \pi (3.5)^2 \]

2. **Calculate \( (3.5)^2 \)**:
\[ (3.5)^2 = 12.25 \]

3. **Substitute \(\pi\) with \(\frac{22}{7}\)**:
\[ A = 4 \times \frac{22}{7} \times 12.25 \]

4. **Calculate \( \frac{88 \times 12.25}{7} \)**:
\[ A = \frac{1078}{7} \approx 154 \text{ cm}^2 \]

### Final Results
- **Volume of the sphere**: \( \approx 179.76 \text{ cm}^3 \)
- **Surface Area of the sphere**: \( 154 \text{ cm}^2 \)