To find the area of a circle using the diameter, you can follow these simple steps:
1. **Know the Formula**: The area (A) of a circle can be calculated using the formula: A = πr², where r is the radius of the circle.
2. **Calculate the Radius**: The diameter (d) of a circle is twice the radius. So, you can find the radius by dividing the diameter by 2: r = d / 2.
3. **Substitute the Radius in the Formula**: Once you have the radius, substitute it back into the area formula. This gives you: A = π(d/2)².
4. **Simplify the Calculation**: You can simplify this to: A = (π/4) × d². This means you can directly calculate the area if you know the diameter.
**Example**: If the diameter of the circle is 10 cm, you first calculate the area as follows:
- Radius = 10 cm / 2 = 5 cm
- Area = π × (5 cm)² = π × 25 cm² ≈ 78.54 cm²
Or using the diameter directly:
- Area = (π/4) × (10 cm)² = (π/4) × 100 cm² ≈ 78.54 cm²
So, regardless of whether you use the radius or the diameter, you arrive at the same area! Simple and effective!