Follow the steps below to construct a triangle with given segment legnth.

First create three different segments that can be used as side lengths of a triangle. They will be labeled a, b and c by default.

1. First create three different segments that can be used as side lengths of a triangle. They will be labeled a, b and c by default.
2. Create a point which will be called A.
3. Select the compass tool and set the radius to the length of segment a and put the center of your circle on the point you just created.
4. Put a point which will be called B on the circle you just created.
5. Select the compass tool again and set the radius to the length of segment b and put the center of the circle on point B.
6. Using the compass tool again set the radius to the length of segment c and put the center of the circle to point A.
7. Create point C where the the two circles you just created intersect.
8. Using the segment tool create segment AC and segment BC.
9. Use the move tool to change the length of segment a.