Finding the Center of the Patio Table

A major hail storm shattered your favorite circular glass patio table. You go online to order a new glass top but you need to know where the center of the glass top is/the radius.[br][br]How can you find the center of the circular glass top so that you can order a new one?
Broken Patio Table
Use the applet and tools below to find the center/radius of your patio table.

Information: Finding the Center of the Patio Table