Answer:
The area of a circle can be found using the formula 
Step-by-step explanation:
1. 12 cents each
2. $1.40
3. 40 mph
In 1500 people of 200 lb each, the total weight would be 300000 lb.
Set up a proportion: 200lb/3.2*10^-5 = 300,000lb/x
(3.2*10^-5*300,000)/200 = x
x = 0.48, I believe
Group x terms
(2x^2+8x)-12=0
undistribute 2
2(x^2+4x)-12=0
take 1/2 of 4 and square it, add negative and positive of it insde (2^2=4)
2(x^2+4x+4-4)-12=0
factor perfect square
2((x+2)^2-4)-12=0
distribute
2(x+2)^2-8-12=0
2(x+2)^2-20=0
add 20 to both sides
2(x+2)^2=20
divide both sides by 2
(x+2)^2=10
sqrt both sides, remember to take positive and negative root
x+2=+/-√10
minus 2 both sides
x=-2+√10 and -2-√10
