Enter Radius Of Bounding Circle And Display Coordinates Of Five Corner Points On Pentagon

(Corner point coordinates) Suppose a pentagon is centered at (0, 0) with one point at the 0 o’clock position. Write a program that prompts the user to enter the radius of the bounding circle of a pentagon and displays the coordinates of the five corner points on the pentagon. Here is a sample run:

Enter the radius of the bounding circle: 100
The coordinates of five points on the pentagon are
(95.1057, 30.9017)
(0.000132679, 100)
(-95.1056, 30.9019)
(-58.7788, -80.9015)
(58.7782, -80.902)

What we know , we know both the radius of the circle(user inputted) and the side of the pentagon from formula (double side = 2 * radius * Math.sin(Math.PI/5)) .We also know that one point is (0 .100) Also i know that the distance between 2 points is Math.sqrt(Math.pow(x1 - x2 ,2) - Math.pow(y1 -y2 ,2)) .

There might be other ways to solve it but this is my best bet trough i dont remember how to solve linear equations of the form x^2 + y^2 = - radius and radius ^2 = x^2 + (y - 100) ^ 2..

The solution i found is using the radius from the center to the point we want to find out and using the radius to the point we already know ( 0 .100) but i have to solve that damn equation first ...