Answer: 40 degrees
Step-by-step explanation:
[tex]\begin{aligned}& \triangle A B C \cong \triangle D E F \\&\therefore \angle A=\angle D \quad(\text{By corresponding parts of a congruent triangle}) \\&x+20=2 x \\&2 x-x=20\\& x=20\\&\therefore m\angle A=x+20=20+20=40^{\circ} \\\end{aligned}[/tex]
