Okay one last time..... I need help finding the value for f....... I tried putting 16.6 then 16.7 for f but both are wrong..... Can you guys please help me? thanks!

Okay one last time I need help finding the value for f I tried putting 166 then 167 for f but both are wrong Can you guys please help me thanks class=
Okay one last time I need help finding the value for f I tried putting 166 then 167 for f but both are wrong Can you guys please help me thanks class=