Letter d. 37 is the anwser
I wrote the number of steps by green. follow them to find the pattern. The zero in the forth column is the reminder.
For the circle of 3x² + 3y² = 75, the radius would be 5, and the center would be (0, 0)
This is because, usual circle equations have only 1 x² and y², so you can divide all terms by 3 to make the equation look normal. This gives you x² + y² = 25.
Since there is nothing being added or subtracted to the x and y values, the center is (0, 0), and the radius is the square root of whatever the values equal, which is √25 = 5.
I hope this helps!
The ratio is equal to 9 parts (5+4=9). Total (720)/ Total parts (9)= 80
80x5=400 (money saved)
80x4= 320 (money spent)