SOLUTION: the area of a circular ring is 90. if the radius of the outer circle forming the ring is 7, what is the radius of the inner circle of the ring? (assume the circles forming the ring

Algebra.Com
Question 258859: the area of a circular ring is 90. if the radius of the outer circle forming the ring is 7, what is the radius of the inner circle of the ring? (assume the circles forming the ring have the same center.)
Answer by Stitch(470)   (Show Source): You can put this solution on YOUR website!
The Area of a circle is
The Area of the circular ring is the difference of the area of the larger circle minus the area of the inner circle.
Given: Radius of the outer circle is 7. The difference of the areas between the two circles is 90
Our Equation:
The left side of the equation can be simplified by dividing both terms by 3.14

Divide both sides by 3.14

Simplify the equation

Add A^2 to both sides

Subtract 28.65 from both sides

Take the square root of both sides

The radius of the inner ring is 4.5

RELATED QUESTIONS

the area of a circular ring is 90.If the radius of the outter circle forming the ring is... (answered by robertb)
The area of a circular ring is 90. If the radius of the outer circle forming the ring is... (answered by ankor@dixie-net.com)
The area of a circular ring is 90 . If the radius of the outer circle forming the (answered by ankor@dixie-net.com)
Dear Math Tutor, A circular ring has a cross section. if outer radius is 22mm and the (answered by KMST)
What is the radius of the ring?... (answered by ikleyn,FrankM)
Diagram of circle with outer edge shaded. The outer circle has diameter 8 inches. The... (answered by josgarithmetic,MathTherapy)
Flying Disc. A plastic flyiing disc is circular and has a circular hole in the middle.... (answered by ptaylor)
I would be very appreciated if someone were to help me answer this problem. A circular... (answered by stanbon)
A ride at an amusement park consists of two circular rings of swings. At full speed the... (answered by KMST)