Answer
m$\angle$7 = 72$^{\circ}$
Work Step by Step
m$\angle$1 = 108$^{\circ}$
By the Corresponding Angles Postulate: m$\angle$1 = m$\angle$5
By the Linear Pair Postulate: m$\angle$5 + m$\angle$7 = 180$^{\circ}$
Substitute the value of 108 into the equation.
108 + m$\angle$7 = 180
Subtract 108 from both sides
108 - 108 + m$\angle$7 = 180 - 108
Simplify. m$\angle$7 = 72$^{\circ}$
