Geometry-lesson.github: |best|

Drag the vertex. Prove them wrong. (Spoiler: On a sphere, it’s more than 180°. We’ll cover that next week.) 👉 [Visit the Live Demo] 👉 [Star us on GitHub]

You can’t grab a triangle and stretch its vertices to see if the angles still add up to 180°. You can’t rotate a 3D solid to see why the volume formula works. You’re expected to memorize, not manipulate. geometry-lesson.github

Head over to (or check the repository on GitHub). Clone it, break it, fix it. And the next time someone tells you that the sum of the angles in a triangle is 180°, don't just nod. Drag the vertex