Question

the diameter of a circle is 4 kilometers. what is the circles area?
round your answer to the nearest hundredth.
square kilometers

Explanation:

Step1: Find the radius

The radius \( r \) of a circle is half of the diameter \( d \). Given \( d = 4\) km, so \( r=\frac{d}{2}=\frac{4}{2}=2\) km.

Step2: Use the area formula

The formula for the area of a circle is \( A=\pi r^{2}\). Substitute \( r = 2\) into the formula: \( A=\pi\times(2)^{2}\).

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Taking \( \pi\approx3.14159\), then \( A = 4\times3.14159=12.56636\approx12.57\) (rounded to the nearest hundredth).

Answer:

\(12.57\) square kilometers