tolong no 12 dan 15 beserta caranya. Mohon dibantu bsk hrus sdh selesai

[tex]ab = 40cm \\ aob = 50 \: derajat \\ cod = 80 \: derajat \\ cd = .......cm \\ ab = aob \\ cd = cod \\ 40 = 50 \\ cd = 80 \\ cd = 320 \div 5 \\ cd = 64[/tex]