In triangle DEFDEFDEF, ED=5cmED = 5\text{cm}ED=5cm and EF=6cmEF = 6\text{cm}EF=6cm. Given that sin(∠DEF)=23\displaystyle \sin(\angle DEF) = \frac{2}{3}sin(∠DEF)=32 and ∠DEF \angle DEF\,∠DEF is acute.
Find the exact value of cos(∠DEF)\cos(\angle DEF)cos(∠DEF)
Find the length of DFDFDF.
Find ∠EFD\angle EFD∠EFD.