Răspuns :
a) AD/DB=AE/EC
AD=15-8=7
7/8=14/16=7/8 adica sunt paralele
b) AE=AC-EC=40-24=16
AD/DB=AE/EC
20/36=16/24
5/9=2/3 == nu sunt paralele
c)AD/DB=AE/EC
6/8=3/4 adica sunt paralele
d) AD/DB=AE/EC
18/9=20/10
2=2 sunt paralele
am folosit teorema lui thales unde se formeaza segmente proportionale
AD=15-8=7
7/8=14/16=7/8 adica sunt paralele
b) AE=AC-EC=40-24=16
AD/DB=AE/EC
20/36=16/24
5/9=2/3 == nu sunt paralele
c)AD/DB=AE/EC
6/8=3/4 adica sunt paralele
d) AD/DB=AE/EC
18/9=20/10
2=2 sunt paralele
am folosit teorema lui thales unde se formeaza segmente proportionale
asemanarea Δ ADE ≈ Δ ABC
a. AD / AB = AE / AC ; ( 15 - 8 ) / 15 = 14 / ( 14 +16)
7 /15 = 14 / 30
7 / 15 = 7 /15 ⇒ DE II BC
b. 20 / ( 20 +36 ) = ( 40 -24 ) / 40 ; 20 / 56 = 16 /40
5 / 14 = 2 / 5 fals
c. AD / DB = AE / EC ; 6 /8 = 3 /4
3 /4 = 3 /4 ⇒ DE II BC
d. AD / AB = AE / AC ; 18 / 27 = 20 / ( 20 +10 )
2 /3 = 20 /30
2 / 3 = 2 / 3 ⇒ DE II BC
a. AD / AB = AE / AC ; ( 15 - 8 ) / 15 = 14 / ( 14 +16)
7 /15 = 14 / 30
7 / 15 = 7 /15 ⇒ DE II BC
b. 20 / ( 20 +36 ) = ( 40 -24 ) / 40 ; 20 / 56 = 16 /40
5 / 14 = 2 / 5 fals
c. AD / DB = AE / EC ; 6 /8 = 3 /4
3 /4 = 3 /4 ⇒ DE II BC
d. AD / AB = AE / AC ; 18 / 27 = 20 / ( 20 +10 )
2 /3 = 20 /30
2 / 3 = 2 / 3 ⇒ DE II BC