Answer
m $\angle$ 5 = 109$^{\circ}$
Work Step by Step
m$\angle$3 = 71$^{\circ}$
By the Interior Angles Postulate: m$\angle$3 + m$\angle$5 = 180∘
Substitute the value of 71 into the equation.
71 + m$\angle$5 = 180
Subtract 71 from 180
Simplify. m$\angle$5 = 109$^{\circ}$