Surface area of a sphere = 4πr^2
4πr^2=100π
Divide both sides by 4π
r^2=100
r=10
The radius is 10 cm.
The answwer
20% of <span>$1,580.00 is X= 1,580 x20/ 100 = $316
</span>
the amount of his paycheck was <span> $316</span>
Ok...so u have 4 people sharing this plan...they each pay for their own data..however, the $ 90 flat rate is split between them equally.
90/4 = 22.5....so each of them pay 22.50 each for the flat rate.
so John's equation is : 22.5 + 0.25x = 147.50
