(39,469.2 - 39,007.2)/17.5 will give you miles per gallon
The total miles driven were 462 miles/17.5 gal = 26.4 miles per gallon
ask your teacher.
use a calculator.
Use math tutoring for this module.
Pay more attention to the lecture.

Formula :
Base²= Hypotenuse² - Perpendicular ²












Remember the a² in formula has nothing to do with the a we have to find. :)
Okay, so:
You would want to find what 1/10 of the laptop costs. That would be the 10% of money left in Kai's account.
So,
423*.1
(you have to turn the percentage into a decimal; 10%= .10
423*.1= 42.3
So, Kai has 42.3 dollars left to buy a scanner. He only has 10% of his bank account left to spend on the scanner.
I hope this helps!
~cupcake