https://www.khanacademy.org/math/revision-mh-math-class-6/x01cb2212e31ce997:week-3/x01cb2212e31ce997:triangles-and-their-properties/v/classifying-triangles_indian_accent 2025-06-05T06:01:43.515132284Z Classifying triangles The video explores how triangles are classified based on their sides and angles. It introduces the terms scalene, isosceles, and equilateral for side lengths, and acute, right, and obtuse for angles. It emphasizes that triangles can be categorized in multiple ways based on these characteristics. Skyloom (Dubbing) video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Classifying triangles The video explores how triangles are classified based on their sides and angles. It introduces the terms scalene, isosceles, and equilateral for side lengths, and acute, right, and obtuse for angles. It emphasizes that triangles can be categorized in multiple ways based on these characteristics. https://cdn.kastatic.org/ka-youtube-converted/9TVBkPHA89Q.mp4/9TVBkPHA89Q.mp4 357 A Tale of Three Intersecting Lines https://www.khanacademy.org/math/cc-fourth-grade-math/plane-figures/imp-classifying-triangles/v/recog-triangles-example 2021-06-30T20:49:34Z Worked example: Classifying triangles Work through sample problems categorizing triangles as scalene, isosceles, equilateral, acute, right, or obtuse.  Sal Khan video https://cdn.kastatic.org/googleusercontent/qapQdpw8cfMHWOibEL9gEkhhXOWIvu6n8Y_-szy7PC0cbCmtzxxeOv-C7x8CAMEDejATzZedt8K1-x02sMnmiZQ Worked example: Classifying triangles Work through sample problems categorizing triangles as scalene, isosceles, equilateral, acute, right, or obtuse.  https://cdn.kastatic.org/ka-youtube-converted/NRS2ZJVVzOI.mp4/NRS2ZJVVzOI.mp4 143 A Tale of Three Intersecting Lines https://www.khanacademy.org/math/cc-fourth-grade-math/plane-figures/imp-classifying-triangles/e/recognizing-triangles 2026-03-10T04:30:37.966653692Z Classify triangles by side lengths Practice identifying triangles by their side-lengths as equilateral, isosceles, or scalene. Christopher Wobbles Seymour exercise https://www.khanacademy.org/math/cc-fourth-grade-math/plane-figures/imp-classifying-triangles/e/identifying-triangles-by-angles 2024-04-02T14:40:11.776966208Z Classify triangles by angles Practice identifying triangles by their angles as acute, right, or obtuse. Lindsay exercise https://www.khanacademy.org/math/7th-engage-ny/engage-7th-module-6/7th-module-6-topic-b/e/constructing-triangles 2026-01-21T14:10:46.416761336Z Constructing triangles Practice constructing triangles. Emily.Hanlon exercise https://www.khanacademy.org/math/revision-mh-math-class-6/x01cb2212e31ce997:week-3/x01cb2212e31ce997:triangles-and-their-properties/v/triangle-inequality-theorem-indian-accent 2025-06-05T06:01:43.515132284Z Triangle inequality theorem Intuition behind the triangle inequality theorem Skyloom (Dubbing) video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Triangle inequality theorem Intuition behind the triangle inequality theorem https://cdn.kastatic.org/ka-youtube-converted/Y7Nj2hbq2Nw.mp4/Y7Nj2hbq2Nw.mp4 305 A Tale of Three Intersecting Lines https://www.khanacademy.org/math/cc-seventh-grade-math/cc-7th-geometry/cc-7th-constructing-geometric-shapes/e/triangle_inequality_theorem 2025-10-14T14:00:50.911555133Z Triangle side length rules Given the lengths of two sides of a triangle, what can we say about the third side? Igor Terzic exercise https://www.khanacademy.org/math/class-7-ncf/x063f95a40c290960:a-tale-of-three-intersecting-lines/x063f95a40c290960:properties-of-triangles-part-2/v/worked-example-triangle-angles-intersecting-lines_indian_accent 2025-06-11T12:53:03.642274817Z Worked example: Triangle angles (intersecting lines) Learn how to find unknown angles in triangles and intersecting lines. We use concepts like supplementary angles (angles that add up to 180°), vertical angles (opposite angles made by two crossing lines), and exterior angles (angles outside a triangle). There are lots of ways to think about this problem. Skyloom (Dubbing) video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Worked example: Triangle angles (intersecting lines) Learn how to find unknown angles in triangles and intersecting lines. We use concepts like supplementary angles (angles that add up to 180°), vertical angles (opposite angles made by two crossing lines), and exterior angles (angles outside a triangle). There are lots of ways to think about this problem. https://cdn.kastatic.org/ka-youtube-converted/gcsBX7aFb2k.mp4/gcsBX7aFb2k.mp4 297 A Tale of Three Intersecting Lines https://www.khanacademy.org/math/revision-mh-math-class-6/x01cb2212e31ce997:week-3/x01cb2212e31ce997:triangles-and-their-properties/v/angles-in-a-triangle-sum-to-180-proof-indian-accent 2025-06-04T10:11:55.11792485Z Angles in a triangle sum to 180° proof The sum of the interior angle measures of a triangle always adds up to 180;. We can draw a line parallel to the base of any triangle through its third vertex. Then we use transversals, vertical angles, and corresponding angles to rearrange those angle measures into a straight line, proving that they must add up to 180. Skyloom (Dubbing) video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Angles in a triangle sum to 180° proof The sum of the interior angle measures of a triangle always adds up to 180;. We can draw a line parallel to the base of any triangle through its third vertex. Then we use transversals, vertical angles, and corresponding angles to rearrange those angle measures into a straight line, proving that they must add up to 180. https://cdn.kastatic.org/ka-youtube-converted/-IR3SJfOjIc.mp4/-IR3SJfOjIc.mp4 247 A Tale of Three Intersecting Lines https://www.khanacademy.org/math/cc-eighth-grade-math/cc-8th-geometry/cc-8th-triangle-angles/e/triangle_angles_1 2026-03-31T08:44:48.259988263Z Find angles in triangles Find missing angle measures in triangles using the properties of general triangles, isosceles triangles, and equilateral triangles. Tomer Gal exercise https://www.khanacademy.org/math/class-7-ncf/x063f95a40c290960:a-tale-of-three-intersecting-lines/x063f95a40c290960:properties-of-triangles-part-2/v/exterior-angle-property-of-a-triangle 2024-05-28T09:47:20.658952794Z Exterior angle property of a triangle We look at the exterior angle property of the triangle and a quick problem on how to apply it. Devashish Phadnis video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Exterior angle property of a triangle We look at the exterior angle property of the triangle and a quick problem on how to apply it. https://cdn.kastatic.org/ka-youtube-converted/RFKQq6yvRSc.mp4/RFKQq6yvRSc.mp4 263 A Tale of Three Intersecting Lines https://www.khanacademy.org/math/class-7-ncf/x063f95a40c290960:a-tale-of-three-intersecting-lines/x063f95a40c290960:properties-of-triangles-part-2/e/understand-exterior-angle-property 2026-04-07T23:17:37.123726494Z Understand triangle exterior angle property Let's learn where and how the triangle exterior angle property can be applied. Aanand exercise https://www.khanacademy.org/districts-courses/geometry-scps-pilot-textbook/x398e4b4a0a333d18:triangle-congruence/x398e4b4a0a333d18:angle-relationships-in-triangles/e/exterior-angle-property-problems 2026-04-07T23:36:17.218592739Z Triangle exterior angle property problems Let's use the exterior angle property to find missing angles. Aanand exercise https://www.khanacademy.org/math/cc-eighth-grade-math/cc-8th-geometry/cc-8th-triangle-angles/e/angles_2 2026-03-31T08:44:48.259988263Z Finding angle measures using triangles Use your knowledge about angles to find missing angle measures in various complex situations. David Lai exercise