https://www.khanacademy.org/math/cc-fifth-grade-math/properties-of-shapes/imp-quadrilaterals-2/v/quadrilateral-overview 2022-11-16T04:22:43.7414897Z Intro to quadrilateral There are many different types of quadrilaterals. A quadrilateral is defined as a two-dimensional shape with four sides, four vertices, and four angles. There are two main types: concave and convex. There are also various subcategories of convex quadrilaterals, such as trapezoids, parallelograms, rectangles, rhombi, and squares. Sal Khan video https://cdn.kastatic.org/googleusercontent/y0z2Dx227KWvT4VD_hG_TqpMYbxEXxdTPRSOKVc6aeWVt99HQzi2PyCHYK-EJWubSGHfH7rO_qaoBpweufvY7mrJ Intro to quadrilateral There are many different types of quadrilaterals. A quadrilateral is defined as a two-dimensional shape with four sides, four vertices, and four angles. There are two main types: concave and convex. There are also various subcategories of convex quadrilaterals, such as trapezoids, parallelograms, rectangles, rhombi, and squares. https://cdn.kastatic.org/ka-youtube-converted/Ka82QC4QvGA.mp4/Ka82QC4QvGA.mp4 504 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 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 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 Quadrilaterals https://www.khanacademy.org/math/geometry/hs-geo-congruence/hs-geo-quadrilaterals-theorems/v/proof-diagonals-of-a-parallelogram-bisect-each-other 2021-02-16T16:08:12Z Proof: Diagonals of a parallelogram Sal proves that a quadrilateral is a parallelogram if and only if its diagonals bisect each other. Sal Khan video https://cdn.kastatic.org/googleusercontent/BoWcWWoNIz6F-yhntRfgBQ16ESP1UFJk_C7gy5uwM6rrCwhcWmf0FcNBsncukkUxi-8eOJOwhbE-pNA3h4-UawCz Proof: Diagonals of a parallelogram Sal proves that a quadrilateral is a parallelogram if and only if its diagonals bisect each other. https://cdn.kastatic.org/ka-youtube-converted/TErJ-Yr67BI.mp4/TErJ-Yr67BI.mp4 546 Quadrilaterals https://www.khanacademy.org/math/revision-up-math-class-7/xad74f3b46242b79b:week-3-revision-up-math-class-7/xad74f3b46242b79b:quadrilaterals-revision-up-math-class-7/e/revision-quadrilaterals-up-math-class-7 2026-04-08T00:54:09.631945657Z Revision Quadrilaterals Practice problems for revision of Quadrilaterals. Satya Swaroop exercise