c04ex07.pyw

from graphics import *
import math

def main():
print("This program computes the intersection of a circle and")
print("a horizontal line.")
print()

radius = float(input("Please enter the radius of the circle: "))
yinter = float(input("Please enter the y-intercept of the line: "))

win = GraphWin("Circle Intersection")
win.setCoords(-10,-10,10,10)

Circle(Point(0,0), radius).draw(win)
Line(Point(-10,yinter), Point(10,yinter)).draw(win)

x = math.sqrt(radius * radius - yinter * yinter)
print("X values of intersection", -x, x)

p1 = Circle(Point(x,yinter),0.25)
p1.setOutline("red")
p1.setFill("red")
p1.draw(win)

p2 = p1.clone()
p2.move(-2*x, 0)
p2.draw(win)

win.getMouse()
win.close()

main()