tolong pake cara...!!!

nomor 9 : segitiga abc sebangun dngn segitiga ade, maka : 21/21+28 = bc/56
21/49 = bc/56
49bc = 56x21
49bc = 1.176
bc = 1.176 / 49 = 24

nomor 10 : segitiga gkc sebangun dngn segitiga gba, maka 4/4+14 = 8/8+ac
4/18 = 8/8+ac
18x8 = 4x (8+ac)
144= 32 + 4ac
4ac = 112
ac = 112/4 = 28