AB=4,AC=2√3,BC=2 ∠C=90 ∠B=60 ∠C=30
AB�0�5=AC�0�5+BC�0�5 BC�0�5=AB�0�5-AC�0�5=4�0�5-(2√3)�0�5=16-12=4 所以:BC=2 因:BC=1/2AB,∠C=90° 所以:∠A=30°; ∠B=90°-30°=60°
BC�0�5=4�0�5-﹙2√3﹚�0�5=16-12=4BC=2