Khan Academy on a Stick
Geometric constructions
We now have fancy computers to help us perfectly draw things, but have you ever wondered how people drew perfect circles or angle bisectors or perpendicular bisectors back in the day. Well this tutorial will have you doing just as your grandparents did (actually, a little different since you'll still be using a computer to draw circles and lines with a virtual compass and straightedge).
Constructing a perpendicular bisector using a compass and straightedge
Constructing a perpendicular line using a compass and straightedge
Constructing an angle bisector using a compass and straightedgeConstructing bisectors of lines and angles
With just a compass and a straightedge (or virtual versions of them), you'll be amazed by how many geometric shapes you can construct perfectly. This tutorial gets you started with the building block of how to bisect angle and lines (and how to construct perpendicular bisectors of lines).
Constructing square inscribed in circle
Constructing equilateral triangle inscribed in circle
Constructing regular hexagon inscribed in circleConstructing regular polygons inscribed in circles
Have you ever wondered how people would draw a square, equilateral triangle or even hexagon before there were computers? Well, now you're going to do just that (ironically, with a computer). Using our virtual compass and straightedge, you'll construct several regular shapes (by inscribing them inside circles).
Constructing circle inscribing triangle
Constructing circumscribing circleConstructing circumcircles and incircles
In our study of triangles, we spent a decent amount of time think about incenters (the intersections of the angle bisectors) and circumcenters (the intersections of the perpendicular bisectors). We'll now leverage this knowledge to actually construct circle inscribed and circumscribed about a triangle using only a compass and straightedge (actually virtual versions of them).