The quantitative relationship of a is as follows: 1 -2 Bar 24 Two triangles abc are straight lines with obtuse triangle angle A greater than 90 degrees and bdce.

BHC=∠EHD。

From the intersection of heights BD and CE at point H, we get

∠ADH=∠AEH=90。

From the theorem of sum of internal angles of quadrilateral

∠A+∠AEH+∠EHD+∠HDA=360，

∠A+∠EHD = 360-∠AEH-∠HDA = 360-90-90 = 180，

∴∠bhc+∠a= 180；

(2) Because ∠BHC and ∠EHD are diagonal, we get

BHC=∠EHD。

From the intersection of heights BD and CE at point H, we get

∠ADH=∠AEH=90。

From the theorem of sum of internal angles of quadrilateral

∠H+∠AEH+∠EHD+∠HDA=360，

∠H+∠DAE = 360-∠AEH-∠HDA = 360-90-90 = 180，

∴∠BHC+∠BAC= 180。