S = [140, 30, 40] + r·([60, 60, 40] - [140, 30, 40]) = [120, 210, 40] + s·([60, 180, 40] - [120, 210, 40])
S = [140, 30, 40] + r·[-80, 30, 0] = [120, 210, 40] + s·[-60, -30, 0] → r = 19/7 ∧ s = 23/7
S = [140, 30, 40] + 19/7·[-80, 30, 0] = [- 540/7, 780/7, 40] = [-77.14, 111.43, 40]
Du hast also alles richtig gemacht. Prima!