Answer:
EF is the longest side of △DEF,
DF = 6 cm and
DE = 6 StartRoot 3 EndRoot cm.
Explanation:
The angle ∠ EDF = 90° of the right triangle Δ DEF and ∠ DEF = 30° and ∠ EFD = 60°.
The hypotenuse EF is 12 cm.
Now, Sin ∠ EFD = DE/EF
⇒
⇒ DE = 6√3 cm.
Again, Cos ∠EFD = DF/EF
⇒
⇒ DF = 6 cm.
Therefore, EF is the longest side of △DEF, DF = 6 cm and DE = 6 StartRoot 3 EndRoot cm. (Answer)