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 and their properties (parallelograms) https://www.khanacademy.org/math/cc-third-grade-math/quadrilaterals-3rd/imp-quadrilaterals/e/categorize-quadrilaterals 2025-02-27T11:46:16.621461116Z Analyze quadrilaterals Classify and compare rectangles, rhombuses, and squares. Erin Kats exercise https://www.khanacademy.org/math/cc-third-grade-math/quadrilaterals-3rd/imp-quadrilaterals/a/identify-quadrilaterals 2021-06-30T20:49:36Z Identifying quadrilaterals Classify quadrilaterals, including rectangles, rhombuses, and squares.  article https://www.khanacademy.org/math/cc-third-grade-math/quadrilaterals-3rd/imp-quadrilaterals/e/identify-quadrilaterals 2026-05-06T05:31:17.506778064Z Identify quadrilaterals Identify squares, rectangles, and rhombuses. Lindsay exercise https://www.khanacademy.org/math/geometry-home/geometry-miscellaneous/geometry-worked-examples/v/ca-geometry-triangles-and-parallelograms 2020-06-23T07:22:43Z CA Geometry: Triangles and parallelograms 21-25, triangles and parallelograms Sal Khan video https://cdn.kastatic.org/googleusercontent/Exk_L39GKlzueYbuRRzit5EhwYJWNRv3uF74WvhbRd0oYerpz61Rdt5M2VReA2rLsdhBgd3zXlXNfAKisRd1EuI0ig CA Geometry: Triangles and parallelograms 21-25, triangles and parallelograms https://cdn.kastatic.org/ka-youtube-converted/h0FFEBHBufo.mp4/h0FFEBHBufo.mp4 674 Quadrilaterals and their properties (parallelograms) https://www.khanacademy.org/math/cc-fourth-grade-math/plane-figures/imp-classifying-geometric-shapes/v/quadrilateral-properties 2021-06-30T20:49:37Z Quadrilateral properties Learn about the properties of quadrilaterals, parallelograms, trapezoids, rhombuses, rectangles, and squares. Sal Khan video https://cdn.kastatic.org/googleusercontent/JGC4e5CKmDPc0EaGsoC76iS72j_U_G4PY5Pqha8QYVqeze74OxRmhuICMKdpz8HS_llastP2FKeGE1eDazyEHLI Quadrilateral properties Learn about the properties of quadrilaterals, parallelograms, trapezoids, rhombuses, rectangles, and squares. https://cdn.kastatic.org/ka-youtube-converted/5CeBlu260Rw.mp4/5CeBlu260Rw.mp4 307 Quadrilaterals and their properties (parallelograms) https://www.khanacademy.org/math/cc-fifth-grade-math/properties-of-shapes/imp-quadrilaterals-2/v/classifying-shapes 2022-11-16T04:22:43.7414897Z Classifying quadrilaterals There are many different relationships between the types of quadrilaterals. Parallelograms have two sets of parallel sides, rhombuses are parallelograms with equal side lengths, and squares are rhombuses with right angles. Though there is overlap, not all quadrilaterals fit into each category. Sal Khan video https://cdn.kastatic.org/googleusercontent/40hO7h2wXw0eS682Y7Paa9uKYSBi0fv_ETPyiO0LA7kAJCT2W5WpF2dZUSnhJOxa7OLWNBha76KeszuEQxxjBwU Classifying quadrilaterals There are many different relationships between the types of quadrilaterals. Parallelograms have two sets of parallel sides, rhombuses are parallelograms with equal side lengths, and squares are rhombuses with right angles. Though there is overlap, not all quadrilaterals fit into each category. https://cdn.kastatic.org/ka-youtube-converted/1pHhMX0_4Bw.mp4/1pHhMX0_4Bw.mp4 148 Quadrilaterals and their properties (parallelograms) https://www.khanacademy.org/math/geometry-home/quadrilaterals-and-polygons/quadrilaterals/e/quadrilateral_angles 2026-03-24T23:41:07.080866137Z Quadrilateral angles Find missing angle measures in quadrilaterals. Igor Terzic exercise 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 and their properties (parallelograms) https://www.khanacademy.org/districts-courses/geometry-scps-pilot-textbook/x398e4b4a0a333d18:polygons-and-quadrilaterals/x398e4b4a0a333d18:properties-of-parallelograms/e/regular-polygons-advanced-8th 2026-04-07T23:17:37.123726494Z Diagonal properties of parallelogram Polygons advanced supriya exercise 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 and their properties (parallelograms) 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 and their properties (parallelograms) https://www.khanacademy.org/math/geometry/hs-geo-congruence/hs-geo-quadrilaterals-theorems/v/proof-rhombus-diagonals-are-perpendicular-bisectors 2021-02-16T16:08:12Z Proof: Rhombus diagonals are perpendicular bisectors Sal proves that the diagonals of a rhombus are perpendicular, and that they intersect at the midpoints of both. Sal Khan video https://cdn.kastatic.org/googleusercontent/LQrBnagaN7-w5xyWQkeeTmgHttSnMTyzZpXBuIeMI4XA5UGHycO2sqqb56yHNoMSYrMZOty8gt9jMCgCjXy2wmap Proof: Rhombus diagonals are perpendicular bisectors Sal proves that the diagonals of a rhombus are perpendicular, and that they intersect at the midpoints of both. https://cdn.kastatic.org/ka-youtube-converted/GDcVdBAnBdU.mp4/GDcVdBAnBdU.mp4 244 Quadrilaterals and their properties (parallelograms) https://www.khanacademy.org/math/geometry-home/quadrilaterals-and-polygons/quadrilaterals/v/whether-a-special-quadrilateral-can-exist 2020-06-23T07:22:42Z Whether a special quadrilateral can exist Proving whether a special quadrilateral can exist or not. Sal Khan video https://cdn.kastatic.org/googleusercontent/nxMVd38hsmjjD2a5sy6evfnmnuBm7LSofzZJ9ELg8xVFRzNf9L8nUy8mUu-2wbeaqngG4W6x5bbGZ5qGZpifCW2P Whether a special quadrilateral can exist Proving whether a special quadrilateral can exist or not. https://cdn.kastatic.org/ka-youtube-converted/6dIMIBO_2mc.mp4/6dIMIBO_2mc.mp4 308 Quadrilaterals and their properties (parallelograms) https://www.khanacademy.org/districts-courses/geometry-scps-pilot-textbook/x398e4b4a0a333d18:polygons-and-quadrilaterals/x398e4b4a0a333d18:properties-of-parallelograms/e/using-properties-basic-8th 2026-03-07T07:20:41.87360937Z Side and angle properties of a parallelogram (level 1) Side and angle properties of a parallelogram (level 1) supriya exercise https://www.khanacademy.org/math/geometry/hs-geo-congruence/hs-geo-quadrilaterals-theorems/e/prove-quadrilateral-properties 2026-04-01T17:08:39.409659895Z Prove parallelogram properties Use transformations, triangle congruency criteria, and line and angle relationship to prove parallelogram properties. Charlotte Auen exercise