https://www.khanacademy.org/math/geometry/hs-geo-circles/hs-geo-inscribed-angles/v/inscribed-angles-exercise-example 2022-10-07T00:00:24.225559754Z Inscribed angles Sal finds a missing inscribed angle using the inscribed angle theorem.  video https://cdn.kastatic.org/ka_thumbnails_cache/88ed8757-3b40-4b35-afd1-f5085a99a2a0_1280_720_base.png Inscribed angles Sal finds a missing inscribed angle using the inscribed angle theorem.  https://cdn.kastatic.org/ka-youtube-converted/aNi1-zeEps8.mp4/aNi1-zeEps8.mp4 80 Angles, secants and tangents of a circle https://www.khanacademy.org/math/geometry/hs-geo-circles/hs-geo-inscribed-angles/e/inscribed_angles_1 2026-03-18T02:40:44.778871182Z Inscribed angles Practice the relationship between inscribed & central angles that are subtended by the same arc length. Marcia Lee exercise https://www.khanacademy.org/math/geometry/hs-geo-circles/hs-geo-inscribed-angles/a/challenge-problems-inscribed-angles 2022-09-10T02:03:40.164764806Z Challenge problems: Inscribed angles Solve two challenging problems that apply the inscribed angle theorem to find an arc measure or an arc length. article https://www.khanacademy.org/math/geometry/hs-geo-circles/hs-geo-inscribed-angles/v/inscribed-and-central-angles 2021-02-16T16:08:14Z Inscribed angle theorem proof Proving that an inscribed angle is half of a central angle that subtends the same arc. Sal Khan video https://cdn.kastatic.org/googleusercontent/b9j8vJI8FRhfQOVZipSvn6bkeJnIdG2zndhPcHLtyAyI6m7Zs0Jl88m3cM7oUASY-r8R79C1Ydvxq8mrdsmqLF-N Inscribed angle theorem proof Proving that an inscribed angle is half of a central angle that subtends the same arc. https://cdn.kastatic.org/ka-youtube-converted/MyzGVbCHh5M.mp4/MyzGVbCHh5M.mp4 856 Angles, secants and tangents of a circle https://www.khanacademy.org/math/geometry/hs-geo-circles/hs-geo-inscribed-angles/a/inscribed-and-central-angles-proof 2026-03-19T10:07:17.424260476Z Inscribed angle theorem proof Proving that an inscribed angle is half of a central angle that subtends the same arc. article https://www.khanacademy.org/math/geometry/hs-geo-circles/hs-geo-inscribed-shapes/v/solving-for-unknown-angle 2022-10-07T00:00:24.225559754Z Inscribed shapes: angle subtended by diameter One method using an inscribed angle intercepting a diameter of a circle. video https://cdn.kastatic.org/ka_thumbnails_cache/44f19821-883b-4c54-a10d-b6efe7573af0_1280_720_base.png Inscribed shapes: angle subtended by diameter One method using an inscribed angle intercepting a diameter of a circle. https://cdn.kastatic.org/ka-youtube-converted/pCLGpRaJfJ8.mp4/pCLGpRaJfJ8.mp4 349 Angles, secants and tangents of a circle https://www.khanacademy.org/math/geometry/hs-geo-circles/hs-geo-inscribed-shapes/v/finding-inscribed-angle-measure 2022-10-07T00:00:24.225559754Z Inscribed shapes: find inscribed angle Using either the inscribed angle theorem or the fact that two inscribed angles that intercept the same arc must be congruent. video https://cdn.kastatic.org/ka_thumbnails_cache/abe47037-3a08-47e2-a585-f7cf9755e600_1280_720_base.png Inscribed shapes: find inscribed angle Using either the inscribed angle theorem or the fact that two inscribed angles that intercept the same arc must be congruent. https://cdn.kastatic.org/ka-youtube-converted/h-_BDon5oes.mp4/h-_BDon5oes.mp4 130 Angles, secants and tangents of a circle https://www.khanacademy.org/math/cc-fourth-grade-math/imp-geometry-2/imp-angles-in-circles/v/angle-measurement-and-circle-arcs 2021-06-30T20:49:37Z Angle measurement & circle arcs Learn to measure angles as part of a circle. Sal Khan video https://cdn.kastatic.org/googleusercontent/0KlI5SnYF2Zl_e19lMG8GtaXMwQ7292ZKQJZMTxKeMT6lfUgeJmgNXix6SJCpTWemHGaMh8EcWQNlJ8DT5lPJlhubQ Angle measurement & circle arcs Learn to measure angles as part of a circle. https://cdn.kastatic.org/ka-youtube-converted/D-EIh7NJvtQ.mp4/D-EIh7NJvtQ.mp4 457 Angles, secants and tangents of a circle https://www.khanacademy.org/math/cc-fourth-grade-math/imp-geometry-2/imp-angles-in-circles/e/angles-in-circles 2025-03-28T04:39:37.342267172Z Angles in circles Solve problems about angles as part of a circle. Lindsay exercise https://www.khanacademy.org/math/cc-fourth-grade-math/imp-geometry-2/imp-angles-in-circles/a/angles-in-circles-word-problems 2024-03-04T04:40:28.626617339Z Angles in circles word problems Practice word problems that involve thinking about angles as part of a circle. article https://www.khanacademy.org/math/geometry/hs-geo-circles/hs-geo-tangents/v/proving-radius-is-perpendicular-to-tangent-line 2022-10-07T00:00:24.225559754Z Proof: Radius is perpendicular to tangent line Sal proves that the radius that connects the intersection point of a tangent line with the circle is perpendicular to the tangent line. video https://cdn.kastatic.org/ka_thumbnails_cache/34b0a898-d2a2-482b-8f82-1a9a124ef762_1280_720_base.png Proof: Radius is perpendicular to tangent line Sal proves that the radius that connects the intersection point of a tangent line with the circle is perpendicular to the tangent line. https://cdn.kastatic.org/ka-youtube-converted/St3MU5i3chc.mp4/St3MU5i3chc.mp4 521 Angles, secants and tangents of a circle https://www.khanacademy.org/math/geometry/hs-geo-circles/hs-geo-tangents/a/determining-if-a-line-is-tangent-by-looking-at-angles 2024-01-22T04:05:23.075087325Z Determining tangent lines: angles Solve two problems that apply properties of tangents to determine if a line is tangent to a circle. article https://www.khanacademy.org/math/geometry/hs-geo-circles/xff63fac4:hs-geo-proofs-with-inscribed-shapes/v/perpendicular-radius-bisects-chord 2021-03-11T05:43:32Z Proof: perpendicular radius bisects chord Simple proof using right triangle-side-hypotenuse (RSH) congruence criterion to show that a radius perpendicular to a chord bisects it Sal Khan video https://cdn.kastatic.org/googleusercontent/IK48kEQiF9D_UideUKYjpUWgJQy-BL-yPzsXd4EdlUfzIiM3WMuGjuORmSVnENVwobuQUelZzii5wi6eRSfK1_H_yg Proof: perpendicular radius bisects chord Simple proof using right triangle-side-hypotenuse (RSH) congruence criterion to show that a radius perpendicular to a chord bisects it https://cdn.kastatic.org/ka-youtube-converted/2NgzruZ4_5c.mp4/2NgzruZ4_5c.mp4 233 Angles, secants and tangents of a circle https://www.khanacademy.org/math/geometry/hs-geo-circles/xff63fac4:hs-geo-proofs-with-inscribed-shapes/v/sss-to-show-a-radius-is-perpendicular-to-a-chord-that-it-bisects 2021-02-16T16:08:13Z Proof: radius is perpendicular to a chord it bisects Sal proves that if a radius in a circle is drawn so it bisects a chord, then the radius is also perpendicular to that chord. The proof uses SSS congruence. Sal Khan video https://cdn.kastatic.org/googleusercontent/k-hnsxxATEcb8lem_K1me8yzljfmfJ4YJyyl2C5uv00btaFD0KOJ0sUJsLvVwCOfP--FaXh2QLUO1P8fbNcvKQvv Proof: radius is perpendicular to a chord it bisects Sal proves that if a radius in a circle is drawn so it bisects a chord, then the radius is also perpendicular to that chord. The proof uses SSS congruence. https://cdn.kastatic.org/ka-youtube-converted/TgDk06Qayxw.mp4/TgDk06Qayxw.mp4 499 Angles, secants and tangents of a circle https://www.khanacademy.org/math/geometry/hs-geo-circles/hs-geo-tangents/v/tangents-of-circles-exercise-examples 2022-10-07T00:00:24.225559754Z Tangents of circles problem (example 1) Sal finds missing angles using the property that tangents are perpendicular to the radius. video https://cdn.kastatic.org/ka_thumbnails_cache/ffdd13c3-687f-4a67-9cb7-37a9c7dba0b2_1280_720_base.png Tangents of circles problem (example 1) Sal finds missing angles using the property that tangents are perpendicular to the radius. https://cdn.kastatic.org/ka-youtube-converted/8vFhNhL-zm8.mp4/8vFhNhL-zm8.mp4 277 Angles, secants and tangents of a circle https://www.khanacademy.org/math/geometry/hs-geo-circles/hs-geo-tangents/v/measure-of-circumscribed-angle 2021-02-16T16:08:13Z Tangents of circles problem (example 2) Sal finds a missing angle using the property that tangents are perpendicular to the radius. Sal Khan video https://cdn.kastatic.org/googleusercontent/zIk6U1r0zx-sDeJtjdZ5HVzX8iVeQdQ9LFVT1U6hv8un3tT2iQbE2-5SDzEj90H27d8QpfOFacEKz8BjTX2iwrI Tangents of circles problem (example 2) Sal finds a missing angle using the property that tangents are perpendicular to the radius. https://cdn.kastatic.org/ka-youtube-converted/ZiqHJwzv_HI.mp4/ZiqHJwzv_HI.mp4 227 Angles, secants and tangents of a circle https://www.khanacademy.org/math/geometry/hs-geo-circles/hs-geo-tangents/v/example-with-tangent-and-radius 2021-02-16T16:08:13Z Tangents of circles problem (example 3) Sal finds a missing length using the property that tangents are perpendicular to the radius. Sal Khan video https://cdn.kastatic.org/googleusercontent/PHVUS7ueki6RvdNDEZpLJMXAaaMEXjdwNAVfyHxQ5iOXhD9XeEZkdPCGehcOGnvaICWUvFBVsFnX0lxGJ4Usxmvz2w Tangents of circles problem (example 3) Sal finds a missing length using the property that tangents are perpendicular to the radius. https://cdn.kastatic.org/ka-youtube-converted/KjQ1KN5GgoE.mp4/KjQ1KN5GgoE.mp4 154 Angles, secants and tangents of a circle https://www.khanacademy.org/math/geometry/hs-geo-circles/hs-geo-tangents/e/central--inscribed--and-circumscribed-angles 2026-05-12T22:00:45.396322128Z Tangents of circles problems Solve problems related to tangents of circles. Sandy Knight exercise https://www.khanacademy.org/math/geometry/hs-geo-circles/hs-geo-tangents/a/challenge-problems-radius-of-a-circle-with-a-tangent 2022-09-10T02:03:40.164764806Z Challenge problems: radius & tangent Solve two challenging problems that apply properties of tangents to find the radius of a circle with a tangent. article https://www.khanacademy.org/math/geometry/hs-geo-circles/hs-geo-tangents/a/challenge-problems-perimeter-of-circumscribing-shapes 2022-09-10T02:03:40.164764806Z Challenge problems: circumscribing shapes Solve two challenging problems that apply properties of tangents to find the perimeter of a circumscribing shape. article