On the basis of the photomicrograph (i.e., the relative amounts of the micro constituents) for the lead-tin alloy shown in Figure 9.17 and the Pb-Sn phase diagram (Figure 9.8), estimate the composition of the alloy, and then compare this estimate with the composition given in the figure legend. 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 the α and β phases as well as the eutectic structure are 11.2, 7.3, and 8.7 g/cm3, respectively; and (3) this photomicrograph represents the equilibrium microstructure at 180°C (355°F).