The measure of the angle is half the measure of the opposite arc.
.. ? = 78°/2 = 39°
It is 4320 multiply all of the terms
The answer is 2.6 hours
To solve you just do 1.5 % 115, which gives you the amount of time per mile, then you use the outcome of the division to multiply by 200 to get 2.6
For simple interest rate,
I=P(i)t
54=900(i)(18/12)
i=54/900*(12/18)=4% annually