https://www.khanacademy.org/math/revision-mh-math-class-6/x01cb2212e31ce997:week-3/x01cb2212e31ce997:quadrilaterals/v/intro-to-quadrilaterals-indian-accent 2025-06-05T06:01:43.515132284Z Intro to quadrilaterals Lets discover attributes and features of four-sided shapes, including parallelograms, rhombuses, rectangles, and squares. Skyloom (Dubbing) video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Intro to quadrilaterals Lets discover attributes and features of four-sided shapes, including parallelograms, rhombuses, rectangles, and squares. https://cdn.kastatic.org/ka-youtube-converted/oVokhHwU9aQ.mp4/oVokhHwU9aQ.mp4 460 Quadrilaterals https://www.khanacademy.org/math/class-9-tg/x06d55bfa213a79fd:quadrilaterals/x06d55bfa213a79fd:types-of-quadrilaterals/v/quadrilateral-types-indian-accent 2025-06-04T10:04:13.13703146Z 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. Kalakrit (Dubbing) video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw 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/ZlQZ0EMCKhc.mp4/ZlQZ0EMCKhc.mp4 168 Quadrilaterals https://www.khanacademy.org/math/class-9-tg/x06d55bfa213a79fd:quadrilaterals/x06d55bfa213a79fd:properties-of-parallelograms/v/proof-opposite-sides-of-a-parallelogram-indian-accent 2025-06-04T10:04:13.13703146Z Proof: Opposite sides of a parallelogram Sal proves that a figure is a parallelogram if and only if opposite sides are congruent. Kalakrit (Dubbing) video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw 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/gtDZ9hSKSUA.mp4/gtDZ9hSKSUA.mp4 509 Quadrilaterals https://www.khanacademy.org/math/class-9-tg/x06d55bfa213a79fd:quadrilaterals/x06d55bfa213a79fd:properties-of-parallelograms/v/proof-opposite-angles-of-a-parallelogram-indian-accent 2025-06-04T10:04:13.13703146Z Proof: Opposite angles of a parallelogram Sal proves that opposite angles of a parallelogram are congruent. Kalakrit (Dubbing) video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Proof: Opposite angles of a parallelogram Sal proves that opposite angles of a parallelogram are congruent. https://cdn.kastatic.org/ka-youtube-converted/60-kf3Cluvc.mp4/60-kf3Cluvc.mp4 248 Quadrilaterals https://www.khanacademy.org/math/class-9-tg/x06d55bfa213a79fd:quadrilaterals/x06d55bfa213a79fd:diagonals-of-a-parallelogram/v/proof-diagonals-of-a-parallelogram-indian-accent 2025-06-04T10:04:13.13703146Z Proof: Diagonals of a parallelogram Sal proves that a quadrilateral is a parallelogram if and only if its diagonals bisect each other. Kalakrit (Dubbing) video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw 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/9gAh2lFz5FI.mp4/9gAh2lFz5FI.mp4 547 Quadrilaterals https://www.khanacademy.org/math/class-9-tg/x06d55bfa213a79fd:quadrilaterals/x06d55bfa213a79fd:more-geometrical-statements/v/special-parallelograms 2025-05-15T14:44:06.823245258Z Special Parallelograms This video explores special parallelograms, breaking down their defining properties. Learn how rectangles have opposite sides that are equal and four right angles, while squares take it further with all sides equal and perfectly symmetrical diagonals. Mahak Wasan video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Special Parallelograms This video explores special parallelograms, breaking down their defining properties. Learn how rectangles have opposite sides that are equal and four right angles, while squares take it further with all sides equal and perfectly symmetrical diagonals. https://cdn.kastatic.org/ka-youtube-converted/dVFp9psjn8c.mp4/dVFp9psjn8c.mp4 322 Quadrilaterals https://www.khanacademy.org/math/class-9-tg/x06d55bfa213a79fd:quadrilaterals/x06d55bfa213a79fd:more-geometrical-statements/v/diagonal-as-an-angle-bisector-in-a-parallelogram 2025-10-06T14:00:44.591197305Z Diagonal as an angle bisector in a parallelogram In this video, we begin by introducing the concept of a corollary—a statement that follows logically from a previously proven theorem. Then we explore a specific corollary in geometry: If a diagonal of a parallelogram bisects an angle, the figure must be a rhombus. Through clear reasoning and visual explanation, we show how this result builds on known properties of parallelograms and rhombuses. You'll see how angle bisection and diagonal behavior reveal deeper symmetry, and why this condition guarantees equal sides. Courses on Khan Academy are always 100% free. Start practicing—and saving your progress—now!Unit link 00:00 What is a corollary? 01:04 Proving the corollary: In a parallelogram, if a diagonal is an angle bisector, it is a rhombus. Khan Academy India is a nonprofit organization with the mission of providing a free, world-class education for anyone, anywhere. We have videos and exercises that have been translated into multiple Indian languages, and 15 million people around the globe learn on Khan Academy every month. Support Us: https://india.khanacademy.org/donate Created by Khan Academy Khan Academy video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Diagonal as an angle bisector in a parallelogram In this video, we begin by introducing the concept of a corollary—a statement that follows logically from a previously proven theorem. Then we explore a specific corollary in geometry: If a diagonal of a parallelogram bisects an angle, the figure must be a rhombus. Through clear reasoning and visual explanation, we show how this result builds on known properties of parallelograms and rhombuses. You'll see how angle bisection and diagonal behavior reveal deeper symmetry, and why this condition guarantees equal sides. Courses on Khan Academy are always 100% free. Start practicing—and saving your progress—now!Unit link 00:00 What is a corollary? 01:04 Proving the corollary: In a parallelogram, if a diagonal is an angle bisector, it is a rhombus. Khan Academy India is a nonprofit organization with the mission of providing a free, world-class education for anyone, anywhere. We have videos and exercises that have been translated into multiple Indian languages, and 15 million people around the globe learn on Khan Academy every month. Support Us: https://india.khanacademy.org/donate Created by Khan Academy https://cdn.kastatic.org/ka-youtube-converted/1CnMOAY1O70.mp4/1CnMOAY1O70.mp4 303 Quadrilaterals https://www.khanacademy.org/math/class-9-tg/x06d55bfa213a79fd:quadrilaterals/x06d55bfa213a79fd:more-geometrical-statements/v/angle-bisectors-of-a-parallelogram-form-a-rectangle 2025-10-27T12:01:04.888258735Z Angle bisectors of a parallelogram form a rectangle In this video, we uncover a surprising geometric result: the angle bisectors of a parallelogram form a rectangle! Through a clear, color-coded, and visually engaging proof, you'll see how this elegant property emerges from symmetry and angle relationships. We break down each step graphically to make the logic easy to follow, helping learners visualize and understand the transformation from parallelogram to rectangle. Courses on Khan Academy are always 100% free. Start practicing—and saving your progress—now!Unit link 00:00 Introduction 00:54 Proof of the corollary: Angle bisectors of a parallelogram form a rectangle Khan Academy India is a nonprofit organization with the mission of providing a free, world-class education for anyone, anywhere. We have videos and exercises that have been translated into multiple Indian languages, and 15 million people around the globe learn on Khan Academy every month. Support Us: https://india.khanacademy.org/donate Created by Khan Academy Khan Academy video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Angle bisectors of a parallelogram form a rectangle In this video, we uncover a surprising geometric result: the angle bisectors of a parallelogram form a rectangle! Through a clear, color-coded, and visually engaging proof, you'll see how this elegant property emerges from symmetry and angle relationships. We break down each step graphically to make the logic easy to follow, helping learners visualize and understand the transformation from parallelogram to rectangle. Courses on Khan Academy are always 100% free. Start practicing—and saving your progress—now!Unit link 00:00 Introduction 00:54 Proof of the corollary: Angle bisectors of a parallelogram form a rectangle Khan Academy India is a nonprofit organization with the mission of providing a free, world-class education for anyone, anywhere. We have videos and exercises that have been translated into multiple Indian languages, and 15 million people around the globe learn on Khan Academy every month. Support Us: https://india.khanacademy.org/donate Created by Khan Academy https://cdn.kastatic.org/ka-youtube-converted/8nw7stDbm48.mp4/8nw7stDbm48.mp4 276 Quadrilaterals https://www.khanacademy.org/math/class-9-tg/x06d55bfa213a79fd:quadrilaterals/x06d55bfa213a79fd:the-midpoint-theorem/v/midpoint-theorem 2025-05-21T09:59:19.381663781Z Midpoint theorem Dive into the mid-point theorem in this comprehensive video! Understand the theorem which states that the line segment joining the midpoints of two sides of a triangle is parallel to the third side and equal to half its length. Learn its proof step-by-step, supported by clear visuals and reasoning. To reinforce your understanding, tackle a practical example problem and see how the theorem is applied in real scenarios. Perfect for mastering this essential geometry concept! Courses on Khan Academy are always 100% free. Start practicing—and saving your progress—now! https://www.khanacademy.org/math/ncert-class-9/x2757d6348a04b24e:quadrilaterals-ncert-new Timestamps: 0:00lntroduction 02:02 Proof of mid-point theorem 06:09 Practice Question Khan Academy India is a nonprofit organization with the mission of providing a free, world-class education for anyone, anywhere. We have videos and exercises that have been translated into multiple Indian languages, and 15 million people around the globe learn on Khan Academy every month. Support Us: https://india.khanacademy.org/donate Created by MAHAK WASAN Mahak Wasan video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Midpoint theorem Dive into the mid-point theorem in this comprehensive video! Understand the theorem which states that the line segment joining the midpoints of two sides of a triangle is parallel to the third side and equal to half its length. Learn its proof step-by-step, supported by clear visuals and reasoning. To reinforce your understanding, tackle a practical example problem and see how the theorem is applied in real scenarios. Perfect for mastering this essential geometry concept! Courses on Khan Academy are always 100% free. Start practicing—and saving your progress—now! https://www.khanacademy.org/math/ncert-class-9/x2757d6348a04b24e:quadrilaterals-ncert-new Timestamps: 0:00lntroduction 02:02 Proof of mid-point theorem 06:09 Practice Question Khan Academy India is a nonprofit organization with the mission of providing a free, world-class education for anyone, anywhere. We have videos and exercises that have been translated into multiple Indian languages, and 15 million people around the globe learn on Khan Academy every month. Support Us: https://india.khanacademy.org/donate Created by MAHAK WASAN https://cdn.kastatic.org/ka-youtube-converted/gutMr88XPcE.mp4/gutMr88XPcE.mp4 403 Quadrilaterals https://www.khanacademy.org/math/class-9-tg/x06d55bfa213a79fd:quadrilaterals/x06d55bfa213a79fd:the-midpoint-theorem/v/converse-of-midpoint-theorem 2025-05-21T09:59:19.381663781Z Converse of midpoint theorem Learn the converse of the mid-point theorem with ease and clarity! This video explains how, when a line passes through the midpoint of one side of a triangle and is parallel to another side, it bisects the third side. With simple visuals, step-by-step reasoning, and examples, you'll not only understand the concept but also know when and how to apply it effectively in various problems! Courses on Khan Academy are always 100% free. Start practicing—and saving your progress—now! https://www.khanacademy.org/math/ncert-class-9/x2757d6348a04b24e:quadrilaterals-ncert-new Timestamps: 0:00-lntroduction 01:51 Proof of converse of mid-point theorem Khan Academy India is a nonprofit organization with the mission of providing a free, world-class education for anyone, anywhere. We have videos and exercises that have been translated into multiple Indian languages, and 15 million people around the globe learn on Khan Academy every month. Support Us: https://india.khanacademy.org/donate Created by MAHAK WASAN Mahak Wasan video https://cdn.kastatic.org/googleusercontent/ZCdwTudJg6e6n-P2gsaUborP4izvMsGo71pvEVlX9dNYWcLXcP7VHkWpn2grt4TUP1KoJLQP9NswyHBuBLSFTBw Converse of midpoint theorem Learn the converse of the mid-point theorem with ease and clarity! This video explains how, when a line passes through the midpoint of one side of a triangle and is parallel to another side, it bisects the third side. With simple visuals, step-by-step reasoning, and examples, you'll not only understand the concept but also know when and how to apply it effectively in various problems! Courses on Khan Academy are always 100% free. Start practicing—and saving your progress—now! https://www.khanacademy.org/math/ncert-class-9/x2757d6348a04b24e:quadrilaterals-ncert-new Timestamps: 0:00-lntroduction 01:51 Proof of converse of mid-point theorem Khan Academy India is a nonprofit organization with the mission of providing a free, world-class education for anyone, anywhere. We have videos and exercises that have been translated into multiple Indian languages, and 15 million people around the globe learn on Khan Academy every month. Support Us: https://india.khanacademy.org/donate Created by MAHAK WASAN https://cdn.kastatic.org/ka-youtube-converted/xIls18K7dm0.mp4/xIls18K7dm0.mp4 300 Quadrilaterals https://www.khanacademy.org/math/revision-tg-math-class-9/x6c9499d6e7016acd:week-2/x6c9499d6e7016acd:quadrilaterals/e/revision-quadrilaterals-tg-class-9 2026-02-18T21:20:35.275198076Z Revision quadrilaterals TG class 9 . Khan Academy exercise