The following formula gives the distance between two points, **(x₁,y₁)** and **(x₂,y₂)** in the Cartesian plane:

sqrt{(x_2 – x_1)^2 + (y_2 – y_1)^2}(x2−x1)2+(y2−y1)2

Given the center and a point on the circle, you can use this formula to find the radius of the circle.

### Instructions

Write a program that prompts the user to enter the center and a point on the circle. The program should then output the circle’s radius, diameter, circumference, and area. Your program must have at least the following functions:

- distance: This function takes as its parameters four numbers that represent two points in the plane and returns the distance between them.
- radius: This function takes as its parameters four numbers that represent the center and a point on the circle, calls the function distance to find the radius of the circle, and returns the circle’s radius.
- circumference: This function takes as its parameter a number that represents the radius of the circle and returns the circle’s circumference. (If r is the radius, the circumference is
*2πr*.) - area: This function takes as its parameter a number that represents the radius of the circle and returns the circle’s area. (If r is the radius, the area is
*πr²*.) Assume that**π = 3.1416**.

Format your output with setprecision(2) to ensure the proper number of decimals for testing!