Add the two numbers 3004000000+2749000000 and divide by 2
which equals 2876500000 or 2.8765x10^9
I'm guessing the 20 percent off is from the $36.81 so you take 36.81 times 0.80 making it $29.448. Take 90 dollars and minus that amount.
Answer: $60.552
Rounded Answer: $60.55 or $60.60 or $61
Not sure if this helped, but yeah.....
19.25 rounded to the nearest ones is 20
C= pi multiplied by diameter
