∫AE:DE = 2: 1
∴AE:AD=2:3
DE:AD= 1:3
Advertising split ∠BAC
∴∠BAE=∠CAD
∠∠ABE =∠C C。
∴△ABE∽△ACD(AA)
∴BE:CD=AE:AD=2:3
∠AEB=∠ADC
∴∠BED=∠BDE (complementary angles of equal angles are equal)
∴BE=BD
∴BD:CD=2:3
So BD: BC = 2: 5.
∫△BDE and△△△ Abd are based on DE and AD, respectively, and have the same height.
∴S△BDE:S△ABD=DE:AD= 1:3
∫△ABD and△△△ ABC are based on BD and BC, respectively, with the same height.
∴S△ABD:S△ABC=BD:BC=2:5
∴s△bde:s△abc(= 1/3×2/5)=2: 15