https://www.khanacademy.org/math/revision-ncert-class-8-math/x46f3ddd31448eca8:week-1/x46f3ddd31448eca8:understanding-quadrilaterals/e/revision-understanding-quadrilaterals-for-ncert-math-class-8 2026-04-07T23:36:17.218592739Z Revision Understanding Quadrilaterals . Aakash Bagga exercise https://www.khanacademy.org/math/geometry-home/geometry-shapes/geometry-curves-and-polygons/v/polygons-as-special-curves-basic-geometrical-ideas-class-6-india-khan-academy 2020-09-30T07:51:31Z Polygons as special curves You may have learnt that triangles, rectangles etc. are all examples of polygons but that circles are not. What exactly makes a curve a polygon? Aanand Srinivas video https://cdn.kastatic.org/googleusercontent/ckRjsH6uJtzQAEOQ-13-vPvrWm1omm0P1j7-mEZDEXFc-yHR5i7-VP9Knj07Q2S7HoHokCB7vUFtVVEuf91ZjPG2 Polygons as special curves You may have learnt that triangles, rectangles etc. are all examples of polygons but that circles are not. What exactly makes a curve a polygon? https://cdn.kastatic.org/ka-youtube-converted/hGRu2Pyl92w.mp4/hGRu2Pyl92w.mp4 193 Understanding Quadrilaterals https://www.khanacademy.org/math/geometry-home/geometry-shapes/angles-with-polygons/v/sum-of-interior-angles-of-a-polygon 2023-04-19T21:01:17.089483175Z Sum of interior angles of a polygon To find the interior angle sum of a polygon, we can use a formula: interior angle sum = (n - 2) x 180°, where n is the number of sides. For example, a pentagon has 5 sides, so its interior angle sum is (5 - 2) x 180° = 3 x 180° = 540°. Sal Khan video https://cdn.kastatic.org/googleusercontent/Dy9dwu-r7REqsvHnPJFG9BZyZgxZhkCsmdatuLMVhinf3RDOohVKv5QYloc5nPaMFXRcHpX97XgtX1-5mr9LXQ4xFA Sum of interior angles of a polygon To find the interior angle sum of a polygon, we can use a formula: interior angle sum = (n - 2) x 180°, where n is the number of sides. For example, a pentagon has 5 sides, so its interior angle sum is (5 - 2) x 180° = 3 x 180° = 540°. https://cdn.kastatic.org/ka-youtube-converted/qG3HnRccrQU.mp4/qG3HnRccrQU.mp4 550 Understanding Quadrilaterals https://www.khanacademy.org/math/geometry-home/geometry-shapes/angles-with-polygons/v/sum-of-the-exterior-angles-of-convex-polygon 2023-05-12T21:01:01.897246564Z Sum of the exterior angles of a polygon Learn a simple and elegant way to find the sum of the exterior angles of any convex polygon. You will see how to redraw the angles adjacent to each other and form a circle. Then you will discover that the sum of the exterior angles is always 360 degrees. Watch this video to master this important skill in geometry. Sal Khan video https://cdn.kastatic.org/googleusercontent/UC5fok88ogGOHxPgpquz_lcohc8q7cIY62SWTfzzJQATMpf7mmAbqUGP8cAnBW4xbNhV7LmbjdYqHsqz0heaI7kf Sum of the exterior angles of a polygon Learn a simple and elegant way to find the sum of the exterior angles of any convex polygon. You will see how to redraw the angles adjacent to each other and form a circle. Then you will discover that the sum of the exterior angles is always 360 degrees. Watch this video to master this important skill in geometry. https://cdn.kastatic.org/ka-youtube-converted/W9B3VYdC5T8.mp4/W9B3VYdC5T8.mp4 324 Understanding Quadrilaterals https://www.khanacademy.org/math/geometry/hs-geo-congruence/hs-geo-quadrilaterals-theorems/v/proof-opposite-sides-of-parallelogram-congruent 2021-02-16T16:08:12Z Proof: Opposite sides of a parallelogram Sal proves that a figure is a parallelogram if and only if opposite sides are congruent. Sal Khan video https://cdn.kastatic.org/googleusercontent/Aou3bes2NVoI_9-pt3FpYxyQjlLKBzk0bwXJZq0kKq94M8q29PBoRIhR6V-0z3AOc8Kl9JWtlmC8n0yfJP3JZJQ Proof: Opposite sides of a parallelogram Sal proves that a figure is a parallelogram if and only if opposite sides are congruent. https://cdn.kastatic.org/ka-youtube-converted/LhrGS4-Dd9I.mp4/LhrGS4-Dd9I.mp4 510 Understanding Quadrilaterals https://www.khanacademy.org/math/geometry/hs-geo-congruence/hs-geo-quadrilaterals-theorems/v/proof-opposite-angles-of-parallelogram-congruent 2021-02-16T16:08:13Z Proof: Opposite angles of a parallelogram Sal proves that opposite angles of a parallelogram are congruent. Sal Khan video https://cdn.kastatic.org/googleusercontent/6y9cgS_Ed8ofB7a7kabkdW7h8oxf3miLKnWKrP1ga4Us7tv5pMbOwfCP37w9HztilyNNuQKK2C0J_Slsai2VzgTd1g Proof: Opposite angles of a parallelogram Sal proves that opposite angles of a parallelogram are congruent. https://cdn.kastatic.org/ka-youtube-converted/oIV1zM8qlpk.mp4/oIV1zM8qlpk.mp4 248 Understanding Quadrilaterals https://www.khanacademy.org/math/cc-fifth-grade-math/properties-of-shapes/imp-quadrilaterals-2/v/quadrilateral-types-exercise 2023-07-17T20:04:18.610848495Z Quadrilateral types Learn to identify quadrilaterals such as kites, trapezoids, parallelograms, rhombuses, rectangles, and squares by side length, presence of parallel sides, and angle type. Sal Khan video https://cdn.kastatic.org/googleusercontent/HUjOvmPMa3weC4ohLEbNYrz2dEK6nSP4Uh1T5bWCrghuhebQwqwRbENk8-hpBp60exi1tPolvDkkOr1U_T96F3y5FQ Quadrilateral types Learn to identify quadrilaterals such as kites, trapezoids, parallelograms, rhombuses, rectangles, and squares by side length, presence of parallel sides, and angle type. https://cdn.kastatic.org/ka-youtube-converted/wPZIa3SjPF0.mp4/wPZIa3SjPF0.mp4 169 Understanding Quadrilaterals