The​ "communication revolution" has given us prepaid phone calling cards. These cards are used to make​ long-distance phone calls from any phone. In a recent year the industry posted sales of ​$. Three years later the sales figure had risen to ​$. What is the increase in sales over the​ three-year period? The increase in sales is ​$ nothing.

Answer is in the photo. I couldn't attach it here, but uploaded it to a file hosting. link below! Good Luck!

cutt.ly/4zZs6GM

definition: a circle is the  set of all points in a plane that are equidistant  from a given  point  called the center of the circle. we use the symbol ⊙ to represent a circle. the a line segment from the center of the circle to  any point  on the circle is a radius of the circle.

step-by-step explanation:

i googled it and this is what i got i don't know how it is. sorry.

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