BD^2=AB^2 - AD^2 = 400 - 256 = 144
BD^2 = 144 = 12^2
BD = 12
Найдем DC:
DC^2 = BС^2 - BD^2 = 169 - 144 = 25
DC^2 = 5^2
DC = 5
BD^2=AB^2 - AD^2 = 400 - 256 = 144
BD^2 = 144 = 12^2
BD = 12
Найдем DC:
DC^2 = BС^2 - BD^2 = 169 - 144 = 25
DC^2 = 5^2
DC = 5