Definition
Rectilinear figure
A rectilinear figure is a closed 2D shape whose straight edges meet in quarter-turns.
Continue from this idea into connected AXIO math.
What it means
Imagine walking around the edge. Every stretch is straight, and every corner turns a quarter-turn left or right. The whole figure can be rotated and still be rectilinear; it does not have to look upright on the page.
Remember it
Straight edges and quarter-turn corners, all the way around.
Example
Starting at one corner of an L-shaped patio, walk 6 m east, 2 m north, 3 m west, 3 m north, 3 m west, then 5 m south back to the start. Each turn is a quarter-turn, so the outline is rectilinear.
Watch for
A closed figure with even one corner where the neighbouring sides are not perpendicular is not rectilinear.
Common mix-up
Rectilinear does not mean rectangular. An L-shape can be rectilinear even though it is not a rectangle.
Exact meaning
A rectilinear figure is a simple closed plane figure whose boundary segments lie in two perpendicular directions, so consecutive sides meet at right angles.