Uploaded August 2026 | Updated September 2026, 2 weeks ago
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khanacademy.org/math/geometry-fl-best/xba45aeb1cf923a80:hs-geo-similarity/xba45aeb1cf923a80:theorems-concerning-trapezoid-properties/v/proof-base-angles-of-isosceles-trapezoids
Let's prove that for isosceles trapezoids (quadrilaterals with one pair of parallel sides and one pair of congruent, non-parallel sides), the base angles are congruent. We can use triangle similarity and the properties of isosceles triangles to help us out.
Khan Academy is a nonprofit organization with the mission of providing a free, world-class education for anyone, anywhere. We offer quizzes, questions, instructional videos, and articles on a range of academic subjects, including math, biology, chemistry, physics, history, economics, finance, grammar, preschool learning, and more. We provide teachers with tools and data so they can help their students develop the skills, habits, and mindsets for success in school and beyond. Khan Academy has been translated into dozens of languages, and 15 million people around the globe learn on Khan Academy every month. As a 501(c)(3) nonprofit organization, we would love your help!
Donate or volunteer today! Donate here: khanacademy.org/donate?utm_source=youtube&utm_medium=desc
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"Courses on Khan Academy are always 100% free. Start practicing—and saving your progress—now!
khanacademy.org/math/geometry-fl-best/xba45aeb1cf923a80:hs-geo-similarity/xba45aeb1cf923a80:theorems-concerning-trapezoid-properties/v/proof-base-angles-of-isosceles-trapezoids
Let's prove that for isosceles trapezoids (quadrilaterals with one pair of parallel sides and one pair of congruent, non-parallel sides), the base angles are congruent. We can use triangle similarity and the properties of isosceles triangles to help us out.
Khan Academy is a nonprofit organization with the mission of providing a free, world-class education for anyone, anywhere. We offer quizzes, questions, instructional videos, and articles on a range of academic subjects, including math, biology, chemistry, physics, history, economics, finance, grammar, preschool learning, and more. We provide teachers with tools and data so they can help their students develop the skills, habits, and mindsets for success in school and beyond. Khan Academy has been translated into dozens of languages, and 15 million people around the globe learn on Khan Academy every month. As a 501(c)(3) nonprofit organization, we would love your help!
Donate or volunteer today! Donate here: khanacademy.org/donate?utm_source=youtube&utm_medium=desc
Volunteer here: khanacademy.org/contribute?utm_source=youtube&utm_medium=desc"
