Answer :
- AC=Hypotenuse=20
- BC=Base=16
AB:-
Apply Pythagorean theorem
[tex]\\ \rm\rightarrowtail P^2=H^2-B^2[/tex]
[tex]\\ \rm\rightarrowtail P^2=20^2-16^2[/tex]
[tex]\\ \rm\rightarrowtail P^2=400-256[/tex]
[tex]\\ \rm\rightarrowtail P^2=144[/tex]
[tex]\\ \rm\rightarrowtail AB=12[/tex]
Now
- DE=AB/3=12/3=4
- EF=BC/3=16/3=5.3
- DF=AC/3=20/3=6.6
Now
[tex]\\ \rm\rightarrowtail sinF=\dfrac{DE}{DF}[/tex]
[tex]\\ \rm\rightarrowtail sinF=\dfrac{4}{6.6}[/tex]
[tex]\\ \rm\rightarrowtail sinF=0.61[/tex]

