Super hard geometry question!!

Question

If you were to describe the parts of the circle, how would you label AB, PQ, ST, SQ and SP? What are the lengths of each segment? 

Answer 1

AB is a chord.

PQ is a diameter

ST is a radius

SQ and SP are also radii.

There is not enough information shown in the diagram to calculate the length of AB (notice there are no restrictions on where it can be), So is could be short or long like this:

But since ST is shown as 6 cm, then SP and SQ are also 6 cm and PQ is 12 cm