Question

如图:己知:AB=AC=DC,AD=BD,求∠BAC的度数

Answer 1

∠B=∠ACB=2∠D

∠BAC=180°-2∠B

∠DAC+∠BAC=∠B

∠B/2+180°-2∠B=∠B

5∠B/2=180°

∠B=72°

∠BAC=180°-72°×2=36°