Bonjour,
Application du théorème de Pythagore.
[tex]el {}^{2} = er {}^{2} + {rl}^{2} [/tex]
[tex] {rl}^{2} = {el}^{2} - {er}^{2} [/tex]
[tex]rl {}^{2} = 150 {}^{2} - 90 {}^{2} [/tex]
[tex] {rl}^{2} = 150 \times1 50 - 90 \times 90[/tex]
[tex] {rl}^{2} = 22 \: 500 - 8100[/tex]
[tex] {rl}^{2} = 14 \: 400[/tex]
[tex]rl = \sqrt{14 \: 400} [/tex]
[tex]rl = 120 \: m[/tex]
