# Compass and Straight Edge Construction

Geometric construction is a classic form of math that studies building forms and shapes using a compass and straight edge. Modern mathematics usually favors the cartesian coordinate system for modeling these types of problems, especially when a computer is involved. That being said, these types of geometric problems are interesting and worth studying as they are useful in construction, art and problem solving in general.

## Constructing Shapes

This example demonstrates how to construct an equilateral triangle using a compass and ruler. An equilateral triangle is a triangle whose sides are of equal length.

How to build the golden rectangle using a compass and ruler. This geometric construction also demonstrates how to find the golden ratio.

This video shows how to construct an ellipse using two tacks, a string, and pencil.

This example demonstrates how to construct an pentagon using a straight edge and ruler. A hexagon is a polygon with five equal length sides.

This example demonstrates how to construct an hexagon using a straight edge and ruler. A hexagon is a polygon with six equal length sides.

## Utility

How to divide an angle into two equal parts using a compass and straight edge.

How to bisect line with compass and straight edge.

How to construct a perpendicular line given a straight line.