tolong jawab pertanyaan itu beserta caranya ya......

a) L = CD × AD = 40 × 30 = 1200
b) AE = ½CD = ½(40) = 20
BF = ½AD = ½(30) = 15
L AEF = AE × BF / 2
= 20 × 15 / 2
= 300/2
= 150
c) = 1200 - 150 = 1050