Answer: x=18, A=80 degrees
Step-by-step explanation:
By AA, we can say that [tex]\triangle ABC \sim \triangle[/tex]DEF. So:
1. Since the lengths of corresponding sides of similar triangles in equal ratio, we can say that
[tex]\frac{AB}{DE}=\frac{AC}{DF}\\\frac{20}{30}=\frac{12}{x}\\\frac{2}{3}=\frac{12}{x}\\\frac{12}{18}=\frac{12}{x}\\x=18[/tex]
2. Since corresponding angles in similar triangles are equal, [tex]\angle A=\angle D=80^{\circ}[/tex]
