Investigating Geometry with GeoGebra

Henrico County Public Schools

What are the relationships between the angles?

READ the instructions on the right and INTERACT with the GeoGebra applet below.

Sorry, the GeoGebra Applet could not be started. Please install Java 1.4 (or later) to use this page.

Given an arbitrary ΔABC and ΔKIJ, determine, if any, the relationships between the angles.

Investigation Steps

Click on the icon to reset the diagram.

Theorem 1 Close

Observe the diagram. What do you notice? Move the blue points A or B. What do you notice about the angles? What is the relationship between the angles? What reason can you give for this relationship?

Theorem 2 Close

Observe the diagram. What do you notice? Move the blue points I or J. What do you notice about the angles? What is the relationship between the angles? What reason can you give for this relationship?

March 2006, Steven Lapinski. Applet created with GeoGebra.    Links: HCPS Geometry Home   HCPS Mathematics Home