import math
# Variables
n = 3;
l = 80; # in mm
d = 76; # in mm
r = 8.5;
# Calculations and Results
V_s = (math.pi/4.) * d * d * l; # in mm**3
V_s = V_s * 10**-3; # in cm**3
# r = 1+ (V_s/V_c)
V_c = (1/(r - 1)) * V_s; # in cm**3
print "volume of cylinder in mm**3 is : ",round(V_c*10**3) #incorrect answer in the textbook
C = V_s * n; # C s math.radians(numpy.tan(s for capacity of engine in cm**3
C = C * 10**-3; # in litre
print "Capacity of the engine in litre is : %.3f"%C