College Physics Problem 1.22

What is the area of a circle 3.102 cm in diameter?


The area of a circle can be computed using the formula below when radius is given.

A=pi r^{2}

We also know that the radius is half the diameter, so the area can be calculated using the formula,

A=pi (frac{d}{2}^{2} )

So, by direct substitution

A=pi left ( frac{3.102  cm}{2} right )^{2}

A=7.557  cm^{2}

The area of the circle is 7.557 square centimeters.