https://www.khanacademy.org/math/geometry/hs-geo-congruence/hs-geo-working-with-triangles/v/figuring-out-all-the-angles-for-congruent-triangles-example 2021-02-16T16:08:14Z Corresponding angles in congruent triangles We write the letters of congruent triangles so their order tells us which parts are corresponding. In this video, Sal uses this notation to solve some angles. Sal Khan video https://cdn.kastatic.org/googleusercontent/eEnreKs4WJtRgKYFzsaghVAqi2enwJ2Yelg0GoyR2JIQufIhkSnFl-ruIzaUZaIdJ6O8Nj1o8Qa0W9DWSgtjnxVn Corresponding angles in congruent triangles We write the letters of congruent triangles so their order tells us which parts are corresponding. In this video, Sal uses this notation to solve some angles. https://cdn.kastatic.org/ka-youtube-converted/aDCXPdzyS0s.mp4/aDCXPdzyS0s.mp4 275 Working with triangles https://www.khanacademy.org/math/geometry/hs-geo-congruence/hs-geo-working-with-triangles/e/congruent_triangles_2 2026-05-06T16:50:54.748971034Z Find angles in congruent triangles Given two triangles, determine whether they are congruent and use that to find missing angle measures. Tomer Gal exercise https://www.khanacademy.org/math/geometry/hs-geo-congruence/hs-geo-working-with-triangles/v/equilateral-and-isosceles-example-problems 2023-06-02T19:09:07.369858129Z Isosceles & equilateral triangles problems Isosceles triangles have two congruent sides and two congruent base angles. Equilateral triangles have all side lengths equal and all angle measures equal. We use these properties to find missing angles in composite figures. The problems are partly from Art of Problem Solving, by Richard Rusczyk. Sal Khan video https://cdn.kastatic.org/googleusercontent/9ixZ7rM7WmqajtAwRS3mCa1C3OYiLZrhx03UfUEQnQjc30b5gO_T-jECLSqXQYGBzsXjvVygQ_ea8Dxp8ySdVShc Isosceles & equilateral triangles problems Isosceles triangles have two congruent sides and two congruent base angles. Equilateral triangles have all side lengths equal and all angle measures equal. We use these properties to find missing angles in composite figures. The problems are partly from Art of Problem Solving, by Richard Rusczyk. https://cdn.kastatic.org/ka-youtube-converted/7FTNWE7RTfQ.mp4/7FTNWE7RTfQ.mp4 387 Working with triangles https://www.khanacademy.org/math/geometry/hs-geo-congruence/hs-geo-working-with-triangles/e/find-angles-in-isosceles-triangles 2026-05-26T15:40:49.528985677Z Find angles in isosceles triangles Find missing angles in isosceles triangles given just one angle. Ben Stenhaug exercise https://www.khanacademy.org/math/geometry/hs-geo-congruence/hs-geo-working-with-triangles/v/another-isosceles-example-problem 2021-02-16T16:08:13Z Finding angles in isosceles triangles The measures of two angles of an isosceles triangle are 3x+5 and x+16. Find all possible values of x. Sal Khan video https://cdn.kastatic.org/googleusercontent/Di19saQ2hF2bAQUfIgi5N5pYjVCgHUdku2TPnPcPkcS_h6JQ9MO7T-9h2PQEf6ma7Mbi88j305q4BzJ9KwspDvWM Finding angles in isosceles triangles The measures of two angles of an isosceles triangle are 3x+5 and x+16. Find all possible values of x. https://cdn.kastatic.org/ka-youtube-converted/ceDV0QBpcMA.mp4/ceDV0QBpcMA.mp4 334 Working with triangles https://www.khanacademy.org/math/geometry/hs-geo-congruence/hs-geo-working-with-triangles/v/example-involving-an-isosceles-triangle-and-parallel-lines 2021-07-02T09:35:33Z Finding angles in isosceles triangles (example 2) Sal combines what we know about isosceles triangles and parallel lines with the power of algebra to solve the angles of an isosceles triangle. Sal Khan video https://cdn.kastatic.org/googleusercontent/bjrNG7nB_NxmKYUnbAB-mGg9JhYHVWrg2a3WO6eJpBxQ7mUuACKFuDwHnzNT3-z0_xttbQ5w6VN5u2a3gp7nQeA Finding angles in isosceles triangles (example 2) Sal combines what we know about isosceles triangles and parallel lines with the power of algebra to solve the angles of an isosceles triangle. https://cdn.kastatic.org/ka-youtube-converted/CVKAro3HUxQ.mp4/CVKAro3HUxQ.mp4 195 Working with triangles