Construction

Copying a Segment Using a String

Using a straightedge and a string, it is possible to construct a copy of a segment.

The following three steps can be used to draw a segment with the same length as AB.

Draw a Segment Longer Than AB

With the straightedge, draw a new segment A'C such that it is longer than AB.

Measure AB with a String

Place one end of the string at A and hold it down. Once done, stretch the string so that it forms a straight line and is aligned with AB. Then, using the pencil, mark the point on the string that is above B. This will be the length of AB.

Measuring the segment AB with the string

Draw B' on the New Segment

Move the end of the string from A to A'. Once again, stretch the string so that it forms a straight line and align it with A'C.

The marked point on the string indicates the location of B'. Then, mark this point on A'C and label it as B'.

Marking the point B on the longer segment

Finally, by erasing the unnecessary part of A'C, a segment whose length is the same as the length of AB will be obtained.

As can be seen, AB and A'B' are copies of each other.

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