Mas mbal tolong dibantu yg nomor 3 dan 5 caranya bagaimana??

3.
8/PQ = 4/13
8x13 = 4PQ
104 = 4PQ
PQ = 104/4
PQ = 26

5.
AD/DE = AB/BC
4/6 = 10/BC
4BC = 60
BC = 60/4
BC = 15