Final answer:
The length of ST is 10 units.
Step-by-step explanation:
To find the length of ST, we can use the midpoint formula. Since U and R are the midpoints of PQ and QS respectively, we can find the lengths of PT and QS by doubling the lengths of UR and RU respectively. We know that RU is 8, so PT is 2 * 8 = 16.
Since PQ is 6, ST can be found by subtracting PT from PQ. So, ST = PQ - PT = 6 - 16 = -10. However, since the length of a line segment cannot be negative, we take the absolute value of -10, making the final answer for ST equal to 10 units.