Ángulo interno y externo de un triángulo
https://www.youtube.com/watch?v=RIIx0r3V7Yw
https://www.youtube.com/watch?v=s1tTky69KVg
https://www.youtube.com/watch?v=ec4yMbCUn7w
https://www.youtube.com/watch?v=Rb-rg4Vqthw
https://www.youtube.com/watch?v=UcLiO6yLJ3s
Teorema de Tales, ejercicios y problemas de aplicación
https://www.youtube.com/watch?v=e_MvZr2sNmo
https://www.youtube.com/watch?v=ryRPSOQQJtc
https://www.youtube.com/watch?v=ejKeW3LrLwk
https://www.youtube.com/watch?v=ifjbo-RyfNE
https://www.youtube.com/watch?v=e2SDoARhAwg
https://www.youtube.com/watch?v=vIT0bP6LoIw
Semejanza de triángulos
https://www.youtube.com/watch?v=KKhEv3wA7kU
https://www.youtube.com/watch?v=Gq1uyLpF_v0
https://www.youtube.com/watch?v=Pgb3H4Su1EY
https://www.youtube.com/watch?v=MZKO1qwnS4w
https://www.youtube.com/watch?v=sDH4ecxqV6o
Ángulos opuestos y adyacentes
https://www.youtube.com/watch?v=GCGNpT72moc
https://www.youtube.com/watch?v=B9Cut6Hq4ZM
https://www.youtube.com/watch?v=6IpebH-ZDSA
https://www.youtube.com/watch?v=Uxw_XeVnd2o
Congruencia de triángulos
https://www.youtube.com/watch?v=AKulvWPoQq4
https://www.youtube.com/watch?v=FBeTFJUPxEA
https://www.youtube.com/watch?v=sO02HO_HPDM
https://www.youtube.com/watch?v=Kpve0f88JZs
https://www.youtube.com/watch?v=kpBtpTT3AL0