Answer:
A. mB = 40°
Step-by-step explanation:
In geometry, congruent figures are identical in form, coinciding exactly when superimposed.
From the diagram,
<CAB = 80°; <EFG = 40° and <FGE = 60°
From triangle ️ EFG,
<GEF + <EFG + <FGE = 180°
》<GEF = 180° - (<EFG + <FGE)
<GEF = 180° - (40° + 60°)
<GEF = 180° - 100°
<GEF = 80°
》<GEF = <CAB = 80°
Also,
》<ACB = <EGF = 60°
<ABC = <EFG = 40°
NB. <ABC = mB
