根据勾股定理,
AB² = AB² + AC² = 3² + 4² = 25 = 5²
所以 AB = 5
因为S △ABC = (1/2)×AC×BC = (1/2)×AB×CD
所以(1/2)×3×4 = (1/2)×5×CD
CD = 12/5
根据勾股定理,
AB² = AB² + AC² = 3² + 4² = 25 = 5²
所以 AB = 5
因为S △ABC = (1/2)×AC×BC = (1/2)×AB×CD
所以(1/2)×3×4 = (1/2)×5×CD
CD = 12/5