Final answer:
The area of a circle with a known diameter is obtained using the formula A = πr², where r is half of the diameter. By substituting this value into the formula, you get the area.
Step-by-step explanation:
To find the area of a circle with a given diameter, we need to understand the formula A = πr², where A is the area and r is the radius of the circle. The radius is half the diameter, so if we know the diameter, we can obtain the radius by dividing it by 2. Substituting this value into the formula will provide the area of the circle.
For example, if the diameter of the circle is 4 units, the radius would be 4/2 = 2 units. So, the area of the circle would be A = π * (2)² = 4π square units.
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