Use the Fo$-$En$-$Di ternary diagram to answer the following questions:

a$)$ What is the composition of the melt appearing first when a solid of the composition Fo$55,$ En$30,$ Di$15$ melts?

b$)$ Report all changes in the phase relations as the melting reaction goes to completion! Each time the phase relations change, report the abundances of all phases and the composition of the melt!

a$)$ Use the $x-Y-Z$ ternary diagram to construct an isothermal section for a temperature of $1100C.$ Label all fields in terms of the stable phases!

b$)$ Give the proportions of phases for isopleths $a,b,$ and $c$ for $1100C$ and $1000C.$

a$)$ Use the $x-Y-Z$ ternary diagram to construct an isothermal section for a temperature of $1100C.$ Label all fields in terms of the stable phases!

b$)$ Give the proportions of phases for isopleths $a,b,$ and $c$ for $1100C$ and $1000C.$

a$)$ Use the final diagram to construct a T$-$X binary section along the red line!

b$)$ Draw schematic cooling trends $($temperature vs$.$ time$)$ for X$1$ to X$6!$