Question #N891

A circle has a diameter of 10 centimeters. What is the area, in square centimeters, of the circle? (Use $\pi = 3.14$)
A. 15.7
B. 31.4
C. 78.5
D. 314

Correct Answer is: C

The area of a circle is given by the formula $A = \pi r^2$, where $r$ is the radius of the circle. Since the diameter is 10 centimeters, the radius is 5 centimeters. Substituting 3.14 for $\pi$ and 5 for $r$ in the formula yields $A = 3.14 \cdot 5^2 = 3.14 \cdot 25 = 78.5$.