Do Three Sides Make a Right?
Work Like an Egyptian
Centuries ago, Egyptians used knotted cords (ropes with knots indicating certain lengths) to measure distances, to construct right triangles, etc. These ancient surveyors used stretched rope to ensure that measurements were consistent. They then used these ropes to redraw property lines after flooding from the Delta river.
Imagine that you are a new surveyor in ancient Egypt and have been given the following knotted ropes, is each rope useful for creating triangles? Give it a try.
![[i]Wilkinson, C. (1986). [i]Harvest Scenes[/i]. [Photograph]. Wiki Commons. [url=https://commons.wikimedia.org/wiki/File:Rope_stretching.jpg]https://commons.wikimedia.org/wiki/File:Rope_stretching.jpg[/url]
[/i]](https://www.geogebra.org/resource/jgjz5xyd/BToZp3HPwNfT2DJn/material-jgjz5xyd.png)
Is It a Triangle?
Drag point(s) , , and/or to attempt to create a triangle. You will know that you have successfully created a triangle when point D matches point A and the inside of the triangle is filled in blue (no longer white).
Zoom in for more precision or zoom out to see more. Click and drag the grid to adjust what you see. You can always click the refresh arrows in the top-right corner to reset to the original figure.
Drag any of the labels to more easily read things such as angle measures.