∠a:∠abc:∠acd=2:3:4
△ABC内角和=180°
所以依比例得:∠a=40°,∠abc=60°,∠acb=80°
四边形AEDH内角和=360°
∠ehd=360°-∠a-∠aec-∠adb=140°
∠ehd=∠bhc
得:∠bhc=140°
∠a:∠abc:∠acd=2:3:4
△ABC内角和=180°
所以依比例得:∠a=40°,∠abc=60°,∠acb=80°
四边形AEDH内角和=360°
∠ehd=360°-∠a-∠aec-∠adb=140°
∠ehd=∠bhc
得:∠bhc=140°