Answer:
Option B. [tex]51.1^o[/tex]
Step-by-step explanation:
we know that
In the right triangle of the figure
The sine of angle theta is equal to divide the opposite side to angle theta by the hypotenuse
so
[tex]sin(\theta)=\frac{DF}{DE}[/tex]
substitute the given values
[tex]sin(\theta)=\frac{7}{9}[/tex]
using a calculator
[tex]\theta=sin^{-1}(\frac{7}{9})=51.1^o[/tex]
