What would be the BEST formula to model the volume of a tree trunk?

The graph below could be the graph of which exponential function?

What is the value of x? enter your answer in the box. (cm)

If your annual gross income is $62,000 and you have one monthly car payment of $335 and a monthly student loan payment of $225, what is the maximum house payment you can afford. consider a standard 28% front-end ratio and a 36% back-end ratio. also, to complete your calculation, the annual property tax will be $3,600 and the annual homeowner's premium will be $360.