## Elementary Geometry for College Students (7th Edition)

m$\angle$3=35$^{\circ}$
Line DB bisects $\angle$ADC so $\angle$1 and $\angle$2 are congruent. Angles 2 and 3 are alternate interior angles so they are also congruent. According to the transitive property, this means that angles 1 and 3 are congruent. m$\angle$1=m$\angle$3=x m$\angle$A+2x=180 110+2x=180 2x=70 x=35 m$\angle$3=35$^{\circ}$