[Tutor] float object not callable error

[Kristinn Didriksson]

Hello,
I an completely new to programming and am trying to teach myself  
Python using Python Programming by John Zelle. Essentially I am an ex- 
tech writer trying to learn how to program.
My system: Mac OS X 10.4, Python 2.5, TextMate editor
Here is the problem:

I get 'float' object not callable error.

I thought this was a conversion error, but it seems to me that it may  
be something else. It will not print x and I don't understand why it  
will not do that. Any help is greatly appreciated.

This is the code below. When I got the error message initially, I  
tried to break it down into smaller bites so I could see the problem  
more clearly. I tried to figure this out myself, but not having any  
luck.

Regards,
Kristinn

# Calculate the area of a triangle. Input the lengths of the sides:  
a, b, c.
# Formulas: (s = a + b + c) / 2
# A = sqrt(s(s - a)(s -b)(s - c))

def main():
	import math
	a, b, c = input("Please enter the sides of the triangle separated by  
commas: ")
	s = (float(a + b + c)/2)
	print s #This is to test the first part of the algorithm--and it fails
	x = (s(s -a)(s -b)(s -c))
	print x
	y = math.sqrt(x)
	print y
	#area = math.sqrt((s)(s - a)(s -b)(s-c)) --this is the formula that  
will not work
	print "This is the area of the traingle: " + area
	
main()

# This algorithm has type conversion problems.
# Error message: 'float' object is not callable