How to Calculate the Area of a Circle: Radius and Diameter Explained
Learn how to find the area of a circle using radius or diameter. Master the formula and apply it in real examples!
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To find the area of a circle, use the formula A = πr² where A is the area and r is the radius. If given the diameter (d), divide it by 2 to find the radius (r = d/2), then apply the formula. For example, if the radius is 3, the area is A = π(3)² = 28.27 square units (using π ≈ 3.14). If the diameter is 8, the radius is 4, making the area A = π(4)² = 50.27 square units.
FAQs & Answers
- What is the formula for the area of a circle? The formula for the area of a circle is A = πr², where A is the area and r is the radius.
- How do I find the radius from the diameter? The radius can be found by dividing the diameter by 2 (r = d/2).
- Can I calculate the area with just the diameter? Yes, by first calculating the radius from the diameter and then using the area formula A = πr².
- What is π (pi) approximated to? Pi (π) is approximately 3.14, although it’s an irrational number and has many more decimal places.