How to identify the segment bisector ?

The graph represents the gallons of water in a water tank with respect to the number of hours since it was completely filled

Idont understand math at all! : o( use this scenario to answer the remaining questions: brenton purchased a new bedroom set for $4,500.00. he lives in arizona and pays a 8.75% sales tax. if he made a 50% down payment and financed the rest, what amount did he finance? what is the total sales tax brenton will pay? enter your answer in currency format, round to the nearest cent. what was brenton's total amount financed? enter your answer in currency format, round to the nearest cent.

Order the measurements from the least to the greatest. 2,720 ml , 24.91 l , 0.0268 kl