tolong bantu jawab ya kak......

3. a) AB/PQ = DC/SR
AB/10 = 12/4
4AB = 120
AB = 120÷4
AB = 30

b) BC/PS = DC/SR
BC/8 = 12/4
4BC = 96
BC = 96÷4
BC = 24

c) AD/QR = DC/SR
AD/6 = 12/4
4AD = 72/4
AD = 72÷4
AD = 18
nomer 4-5 saya tdk tau.
semoga membantu:)