Use tangent.
[tex]tangent=\dfrac{opposite}{adjacent}[/tex]
[tex]\tan(m\angle F)=\dfrac{DE}{EF}[/tex]
We have:
[tex]m\angle F=32^o,\ DE=15[/tex]
Substitute:
[tex]\tan32^o=\dfrac{15}{EF}\\\\\tan32^o\approx0.6249\\\\\dfrac{15}{EF}=0.6249\\\\\dfrac{15}{EF}=\dfrac{6249}{10000}\ \ \ \ |\text{cross multiply}\\\\6249EF=150000\ \ \ \ |\text{divide both sides by 6249}\\\\EF\approx24[/tex]
Answer: 24.0
