https://www.khanacademy.org/math/geometry/hs-geo-similarity/xff63fac4:hs-geo-proving-relationships-using-similarity/v/exploring-medial-triangles 2021-04-21T12:03:02Z Exploring medial triangles The three midsegments (segments joining the midpoints of the sides) of a triangle form a medial triangle. Find out the properties of the midsegments, the medial triangle and the other 3 triangles formed in this way. Sal Khan video https://cdn.kastatic.org/googleusercontent/LVJ6ro_jdgfVM67FNz-1vT__NgvQZEdNdgwKKTKAyqFYQ8uNKdND9hPuxplQLo0N90lx2xNWnWJo7pV-yQobDAQ Exploring medial triangles The three midsegments (segments joining the midpoints of the sides) of a triangle form a medial triangle. Find out the properties of the midsegments, the medial triangle and the other 3 triangles formed in this way. https://cdn.kastatic.org/ka-youtube-converted/Rsi5mzEaCPw.mp4/Rsi5mzEaCPw.mp4 693 Congruence proof 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 Congruence proof https://www.khanacademy.org/math/geometry/hs-geo-congruence/hs-geo-bisectors/e/justify-constructions-using-triangle-congruence 2026-04-13T10:20:50.054695382Z Justify constructions Use triangle congruence criteria and line and angle relationships to justify geometric constructions of congruent angles, angle and segment bisectors, parallel lines, and perpendicular lines. Charlotte Auen exercise