$\overleftrightarrow{MK}$ and $\overleftrightarrow{NJ}$ are parallel lines.
The interior angles of a triangle sum to $180^\circ$.
**Complete the equations to prove that corresponding angles always have equal measure.**

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$\text{In terms of } \purple c \text{ and a number} \\\text{in degrees,}$ | $\green b=$ | [[☃ expression 1]]
$\text{In terms of } \purple c \text{ and a number} \\\text{in degrees,}$ | $\pink a=$ | [[☃ expression 2]] |
$\text{Combining these equations to } \\ \text{get } \green b \text{ in terms of } \pink a,$ | $\green b=$ | [[☃ expression 4]]