Proof: Opposite angles of parallelogram congruent | Quadrilaterals | Geometry | Khan Academy

Showing that opposite angles of a parallelogram are congruent

Missed the previous lesson?

Geometry on Khan Academy: We are surrounded by space. And that space contains lots of things. And these things have shapes. In geometry we are concerned with the nature of these shapes, how we define them, and what they teach us about the world at large--from math to architecture to biology to astronomy (and everything in between). Learning geometry is about more than just taking your medicine ("It's good for you!"), it's at the core of everything that exists--including you. Having said all that, some of the specific topics we'll cover include angles, intersecting lines, right triangles, perimeter, area, volume, circles, triangles, quadrilaterals, analytic geometry, and geometric constructions. Wow. That's a lot. To summarize: it's difficult to imagine any area of math that is more widely used than geometry.

About Khan Academy: Khan Academy offers practice exercises, instructional videos, and a personalized learning dashboard that empower learners to study at their own pace in and outside of the classroom. We tackle math, science, computer programming, history, art history, economics, and more. Our math missions guide learners from kindergarten to calculus using state-of-the-art, adaptive technology that identifies strengths and learning gaps. We've also partnered with institutions like NASA, The Museum of Modern Art, The California Academy of Sciences, and MIT to offer specialized content.

For free. For everyone. Forever. #YouCanLearnAnything

Subscribe to Khan Academy’s Geometry channel:

[sanak]

What category can I find these vids under? I would like to start from the beginning!

[krishnac]

This is actually a dry topic, but Khan Academy lectures made it interesting. The only criteria is you should listen to the previous lectures about corresponding angles, interior angles, and congruence theorems with full concentration.

[deutschlernen]

Wait can't you use vertical angles to know that D=A and B=C so the angles must be congruent for them to be equal.

[colinmaxwelljones]

I feel like by teachers forcing students to do this it takes the interest about it away.

[yogalegend]

Géry Bas c'est sée vidéo le manque mal Guen poste anh vidéo.