Aidez moi s'il vous plaît !

BH = BD/2
BD² = BC² + CD² = 230² + 230² = 2*230²
BH = 230V2 / 2 = 115V2
tg(ABH) = AH/BH = 147/115V2 = 0.9
ABH = 42°

IH² = BH² - BI²
BI = BC/2 = 115
IH² = (115V2)² - 115² = 115²
tg(AIH) = AH/IH = 147/115 = 1.28
AIH = 52°