SOLUTION: If the radius of a circle is decreased by 2 meters, the area of the circle is decreased by 80 pie m squared. what is the radius of the original circle?

Algebra.Com
Question 773471: If the radius of a circle is decreased by 2 meters, the area of the circle is decreased by 80 pie m squared. what is the radius of the original circle?
Found 2 solutions by lwsshak3, MathTherapy:
Answer by lwsshak3(11628)   (Show Source): You can put this solution on YOUR website!
If the radius of a circle is decreased by 2 meters, the area of the circle is decreased by 80 pie m squared. what is the radius of the original circle?
***
let r=radius of original circle
r-2=radius of circle decreased by 2 meters
area of circle=π*radius^2
...
πr^2-π(r-2)^2=80π
π cancels out
r^2-(r^2-4r+4)=80
r^2-r^2+4r-4=80
4r=84
r=21
radius of the original circle=21 meters

Answer by MathTherapy(10552)   (Show Source): You can put this solution on YOUR website!

If the radius of a circle is decreased by 2 meters, the area of the circle is decreased by 80 pie m squared. what is the radius of the original circle?

Original radius: m

You can do the check!!

Further help is available, online or in-person, for a fee, obviously. Send comments, “thank-yous,” and inquiries to “D” at MathMadEzy@aol.com

RELATED QUESTIONS

If the radius of a circle is decreased by 40% , by what percent is the area decreased... (answered by Alan3354)
If the radius of a circle is decreased by 10%,by what percent is it's area... (answered by addingup)
if the area of a circle is pie(2x squared+16x+7) what is the... (answered by Theo)
If a circle with a radius of 10 has its radius decreased by 2 , by what percent is the... (answered by Alan3354,nerdybill)
The area of a circle of radius r is given by the polynomial pie r^2. Where pie is an... (answered by ikleyn,Alan3354)
If the radius of a circle is reduced by 10 percent, by what percent is the area... (answered by Alan3354)
the radius of a circle is decreased by 8%. The % difference of the area of the circle is? (answered by Fombitz)
If the sides of a square are decreased by 2 cm, the area is decreased by 36 cm squared.... (answered by Earlsdon)
Hi, my question is: By what product must the radius of a circle be decreased in order to... (answered by ptaylor)