Unit 1.7

GEOMETRIC
CONSTRUCTION

Before computers, before calculators, there was the Compass and the Straightedge. This is the ancient game of creating perfect shapes without measuring numbers.

THE TOOLKIT

No rulers allowed.
Only straight lines.

The Compass

Distance Transfer

Can only draw circles or arcs. It essentially "captures" a distance between two points and moves it elsewhere.

The Straightedge

Line Creation

Can only connect two points with a straight line. It has NO markings (it is not a ruler).

The Blueprint Lab

Select a blueprint below to begin construction. Use the tabs to switch between the Perpendicular Bisector, the Angle Bisector, and the Equilateral Triangle.

Construction Lab

Perpendicular Bisector

1.Start with Segment AB.

2.Compass at A. Set radius > ½ length.

3.Compass at B. Keep SAME radius.

4.Mark intersections C and D.

5.Connect C and D to bisect AB.

Step 1 / 5

Classic Moves

Perpendicular Bisector

4 Steps

The most powerful move in geometry. It finds the midpoint of a segment and creates a 90° intersection simultaneously.

Angle Bisector

4 Steps

Splitting an unknown angle perfectly in half without measuring degrees.

Equilateral Triangle

3 Steps

The simplest construction. Creates a shape with perfect 60° angles and equal sides.