Answer
m$\angle$ABD=56$^{\circ}$
Work Step by Step
Given:
support system of a bridge which has
AC=6ft
m$\angle$ABC=28$^{\circ}$
m$\angle$CBD=m$\angle$ABC=28$^{\circ}$ because they are corresponding angles of congruent triangles
therefore,
m$\angle$ABD=m$\angle$ABC+m$\angle$CBD
m$\angle$ABD=28$^{\circ}$+28$^{\circ}$
m$\angle$ABD=56$^{\circ}$
