Stage 28 · Solid Geometry & Views

28.5.2 The Basic Facts of a Plane

28.5 Points, Lines, and Planes in Space: How the Three Get Along

Point 2 of 5

28.5.2 The Basic Facts of a Plane

Core idea

Why a tripod stands steady: three non-collinear points fix one plane, and once two points lie in a plane, the whole line through them does too.

Module goal. Build the language and basic facts of spatial position, sorting out how points, lines, and planes intersect or run parallel, to lay the groundwork for judging parallelism and perpendicularity.
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