On the basis of the photomicrograph (i.e., the relative amounts of the micro constituents) for the iron-carbon alloy shown in Figure 9.30 and the Fe-Fe3C phase diagram (Figure 9.24), estimate the composition of the alloy, and then compare this estimate with the composition given in the figure legend of Figure 9.30. Make the following assumptions:

(1) The area fraction of each phase and micro constituent in the photomicrograph is equal to its volume fraction;

(2) The densities of proeutectoid ferrite and pearlite are 7.87 and 7.84 g/cm3, respectively;

(3) This photomicrograph represents the equilibrium microstructure at 725(C.