tolong pake cara makasih

L ABC = ½.AC.BC.sin <C
L ABC = ½(4)(4).sin 120
L ABC = 8.(√3/2)
L ABC = 4√3

L BDE = ½.DE.BE.sin <E
L BDE = ½(2)(2).sin 120
L BDE = 2.(√3/2)
L BDE = √3

L ADEC = L ABC - L BDE = 4√3 - √3
= 3√3