AD |
DB |
AE |
EC |
∴
AD |
AB |
AE |
AC |
又∵∠A=∠A,
∴△ADE∽△ABC,
∴∠ADE=∠B,
∴DE∥BC,
∴
AB |
DB |
AC |
EC |
(2)∵AC=3,EC=1,
∴AE=AC-EC=2,
∴
AD |
DB |
AE |
EC |
∴
S△ACD |
S△BCD |
AD |
BD |
∴S△ACD=2S△BCD,
∵S△ABC=S△ACD+S△BCD=3S△BCD,
∴
S△ABC |
S△BCD |
AD |
DB |
AE |
EC |
AB |
DB |
AC |
EC |
S△ABC |
S△BCD |
AD |
DB |
AE |
EC |
AD |
AB |
AE |
AC |
AB |
DB |
AC |
EC |
AD |
DB |
AE |
EC |
S△ACD |
S△BCD |
AD |
BD |
S△ABC |
S△BCD |