2) BC = racine(6² - 3²) = racine(27) = 3racine(3)
3) tan(BAC) = BC/AC = racine(3)
tan(BAC) = BD/BA = BD/6
BD = 6 tan(BAC) = 6racine(3)
4) AD = racine(BA² + BD²) = racine(36 + 108) = racine(144) = 12 cm
CD = AD - AC = 9 cm
5) p = 6 + 12 + 6racine(3) = 18 + 6racine(3) = 28.4 cm
S = 6x6racine(3) = 36racine(3) = 62.4 cm²
