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**To erect a perpendicular to a chain line from a point on it **

The method of establishing perpendiculars with the tape is base on familiar geometric construction. The flowing is same of the methods most commonly used.## 3.4.5. method

Establish at point A at a distance of 3m from C. put zero end end of the tape (10m long) at A end the 10m end at C. the 5m and 6m mark brought together to from a loop of 1m. the tape is now stretched tight by fastening the end A and C. the point A is thus establish the angle BCA will be 900 one person can be set out angle by this method.

## 2nd method

Select E and F Equidistant from C hold the zero end on the tape at E and 10 meter end at F. pickup 5m mark, stretch the tight and establish D. joint DC .

## 3rd method

Select any point F outside the chain line preferably at 5m distance from C. hold 5m mark at F 20m mark at C Witch as center draw and arg to cut the line at E. join EF and produce in to D such that EF = FD = 5m. next dust point D will lie at the 10m mark of the tape head along EF with end zero at E join DC.

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