Construct a parallelogram AB is 8cm ABC is 120 degrees and BC is 5cm

ok. now what?

To construct a parallelogram ABC given the length of AB, the angle at A, and the length of BC, follow these steps:

1. Draw a line segment AB, measuring 8 cm.
2. At point A, draw a ray, AX, making an angle of 120 degrees with AB.
3. Using a compass, measure a distance of 5 cm starting from point A along the ray AX. Label this point B.
4. Connect points B and C to complete the parallelogram ABC.

Note: The opposite sides of a parallelogram are equal in length and parallel to each other, and the opposite angles are also equal. So, if AB is parallel to BC, then CD will also be 8 cm, making AD and BC equal and parallel.