Constructing a 90° (right) angle

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See also the animated version.

After doing this Your work should look like this
Start with a ray with endpoint C. The right angle will have C as its vertex.
1.  Mark a point, not on the given line, about 6 cm in from C. Its exact location is not important. Label it D.
2.  Set the compasses on point D and set their width to the endpoint C .
3.  Draw an arc that crosses the given line and extends over and above the endpoint C. (If you prefer, draw a complete circle.)
4.  Draw a diameter through D from the point where the arc crosses the given line, creating points B and A.
5.  Draw a line from C to the endpoint A of the diameter line
6.  Done. The angle ACB is a right angle (90 deg).  
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Other constructions pages on this site




Right triangles

Triangle Centers

Circles, Arcs and Ellipses


Non-Euclidean constructions