Final answer:
By leveraging the properties of a perpendicular bisector, we can determine that XY is the sum of XO and YO, which are both equal to 10, resulting in a length of 20 for XY.
Step-by-step explanation:
The question pertains to the properties of a perpendicular bisector in a geometric context. Since CO is the perpendicular bisector of both X and ST, and we're given that CY = 20, we can deduce that O is the midpoint of XS and YT. This means that XO = OS and YO = OT. Given that CO is perpendicular to XS and ST, we can infer that XO = OS and YO = OT are equal in length too. Therefore, if CY (the whole length from C to Y) is 20, then YO (half of that length due to the bisector) is 10. Similarly, XO is also 10. To find XY, we simply add the lengths of XO and YO, since XY extends from X, through O, and on to Y. Hence, XY = XO + YO = 10 + 10 = 20.