10. a.) determine the ratio of the three phases present. show your work with clear labels and references to the diagram so that the source of your numbers is obvious.

b.) at what temperature will φ next change? what occurs at this temperature? what is the name of the point intersected? describe the composition of each phase present. derive the variance. what does f imply?

c. can you determine the ratios of the phases present under these conditions? why or why not? does cooling from this point represent a continuous or discontinuous reaction? write the reaction.