DP Math AA · HL / SL · Geometry & Trigonometry

SL 3.1—3d space, volume, angles, distance, midpoints

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Introduction to 3D Coordinate Space

In 2D, every point is described by two coordinates (x,y). Moving into three-dimensional space simply adds a third axis , the z-axis , perpendicular to both the x- and y-axes. Every point in 3D space is then described by an ordered triple (x,y,z).

3D Coordinate System: A system that locates points in space using three mutually perpendicular axes: the x-axis, y-axis, and z-axis. A point is written as (x,y,z), where each value measures the signed distance from the origin along its respective axis.

Think of the origin as the corner of a room: the x-axis runs along one wall, the y-axis along the other wall, and the z-axis runs straight up toward the ceiling.

Note

All the familiar 2D formulas , distance, midpoint, gradient , have direct 3D counterparts. The key idea is simply that you now have a third coordinate to account for in every calculation.

Introduction to 3D Coordinate Space
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Next topic →SL 3.2—2d and 3d trig, sine rule, cosine rule, area
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