https://www.khanacademy.org/math/revision-term-1-mh-math-class-7/x0bdc8a5f9d8ec377:week-2/x0bdc8a5f9d8ec377:angles-and-pairs-of-angles/v/triangle-exterior-angle-example-indian-accent 2025-06-04T10:04:13.13703146Z Triangle exterior angle example An exterior angle is formed outside a triangle by extending a side. Its measure is equal to the sum of the two non-adjacent interior angle measures, thanks to the fact that all angle measures in a triangle add up to 180 degrees. Skyloom (Dubbing) video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Triangle exterior angle example An exterior angle is formed outside a triangle by extending a side. Its measure is equal to the sum of the two non-adjacent interior angle measures, thanks to the fact that all angle measures in a triangle add up to 180 degrees. https://cdn.kastatic.org/ka-youtube-converted/g2bHflif-VI.mp4/g2bHflif-VI.mp4 349 Triangles https://www.khanacademy.org/math/class-7-ncf/x063f95a40c290960:geometric-twins/x063f95a40c290960:congruence-of-triangles/v/triangle-congruence-postulatescriteria-indian-accent 2025-06-04T10:04:13.13703146Z Triangle congruence postulates/criteria This video introduces and justifies the SSS, SAS, ASA and AAS postulates for congruent triangles. He also shows that AAA is only good for similarity. For SSA, better to watch next video. Kalakrit (Dubbing) video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Triangle congruence postulates/criteria This video introduces and justifies the SSS, SAS, ASA and AAS postulates for congruent triangles. He also shows that AAA is only good for similarity. For SSA, better to watch next video. https://cdn.kastatic.org/ka-youtube-converted/QtFJGJ5nESI.mp4/QtFJGJ5nESI.mp4 807 Triangles https://www.khanacademy.org/math/class-7-ncf/x063f95a40c290960:geometric-twins/x063f95a40c290960:congruence-of-triangles/v/why-ssa-isnt-a-congruence-postulatecriterion 2025-06-04T10:04:13.13703146Z Why SSA isn't a congruence postulate/criterion There are some cases when SSA can imply triangle congruence, but not always. This is why it's not like the other triangle congruence postulates/criteria. Kalakrit (Dubbing) video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Why SSA isn't a congruence postulate/criterion There are some cases when SSA can imply triangle congruence, but not always. This is why it's not like the other triangle congruence postulates/criteria. https://cdn.kastatic.org/ka-youtube-converted/WQIMga8hsek.mp4/WQIMga8hsek.mp4 444 Triangles https://www.khanacademy.org/math/class-9-tg/x06d55bfa213a79fd:triangles/x06d55bfa213a79fd:properties-of-triangles/v/proofs-concerning-isosceles-triangles-indian-accent 2025-06-04T10:04:13.13703146Z Proofs concerning isosceles triangles Lets proves that the base angles in isosceles triangles are congruent, and conversely, that triangles with congruent base angles are isosceles. He also proves that the perpendicular to the base of an isosceles triangle bisects it. Aakash Bagga video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Proofs concerning isosceles triangles Lets proves that the base angles in isosceles triangles are congruent, and conversely, that triangles with congruent base angles are isosceles. He also proves that the perpendicular to the base of an isosceles triangle bisects it. https://cdn.kastatic.org/ka-youtube-converted/SV5MpEfTYOg.mp4/SV5MpEfTYOg.mp4 543 Triangles https://www.khanacademy.org/math/in-class-10-math-foundation/x2f38d68e85c34aec:triangles/x2f38d68e85c34aec:proofs-using-congruence/v/geometry-proof-problem-congruent-segments-indian-accent 2025-06-04T10:04:13.13703146Z Geometry proof problem: congruent segments Lets prove that two pairs of segments are congruent using the ASA and AAS congruence criteria. Skyloom (Dubbing) video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Geometry proof problem: congruent segments Lets prove that two pairs of segments are congruent using the ASA and AAS congruence criteria. https://cdn.kastatic.org/ka-youtube-converted/k4fMbujX0mw.mp4/k4fMbujX0mw.mp4 687 Triangles https://www.khanacademy.org/math/in-class-10-math-foundation/x2f38d68e85c34aec:triangles/x2f38d68e85c34aec:proofs-using-congruence/v/geometry-proof-problem-squared-circle-indian-accent 2025-06-04T10:04:13.13703146Z Geometry proof problem: squared circle Lets find a missing angle using triangle congruence in a diagram that contains sector of a circle inscribed within a square. Skyloom (Dubbing) video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Geometry proof problem: squared circle Lets find a missing angle using triangle congruence in a diagram that contains sector of a circle inscribed within a square. https://cdn.kastatic.org/ka-youtube-converted/cMtOAnODjPI.mp4/cMtOAnODjPI.mp4 459 Triangles https://www.khanacademy.org/math/revision-mr-class-9-term-2/x6e82706cbb5834ba:week-1/x6e82706cbb5834ba:triangles/e/revision-triangles-mh-class-9 2026-02-03T09:22:16.808346173Z Revision triangles MH class 9 . Khan Academy exercise