IGD Dropping a Perpendicular Line

• ## IGD: Dropping a Perpendicular Line

Constructing a line perpendicular to a given line and through a point not on the line is one of the most important constructions in geometry. This process is known as dropping a perpendicular, because a perpendicular line is "dropped" from the point to the line.

### Instructions

How to Use

·  Use the points on the sliders to adjust the radii of the circles.

·  You can drag points to change the location and orientation of the construction.

Buttons

The buttons will appear sequentially.

The Reset button will allow you to start over.

### Exploration

• Construct a proof of this construction. If you need a hint, click on the Hint- Why It Works button at the end of the construction.
•  Where do you see perpendicular lines in real-life.
•  Create a scenario where you would need to drop a perpendicular line from a specific point.

### Objectives and Standards

NCTM Standards and Expectations
• Geometry / Measurement
• Understand that by similarity, side ratios in right triangles are properties of the angles in the triangle, leading to definitions of trigonometric ratios for acute angles.
• High School (9-12)
• Geometry