"Published in Newark, California, USA"
A metal washer 1 in. in diameter is pierced by a ½ in hole. What is the area of one face of the washer?
Solution:
To illustrate the problem, it is better to draw the figure as follows
 |
| Photo by Math Principles in Everyday Life |
A metal washer is made from two concentric circles and its a ring shape.
Let d1 = be the diameter of outer circle
d2 = be the diameter of inner circle
A1 = be the area of large circle
A2 = be the area of small circle
Area of Large Circle:
Area of Small Circle:
Therefore, the area of a metal washer is
