math
posted by dan .
The larger circle has a radius that is 18 inches longer than the smaller circle. The larger circle has a circumference that is A pi feet larger then the smaller circle. find the value of a.

Radius of smaller circle: a18 (inchs)
Radius of larger circle: a (inchs)
Circumference of smaller circle:
2*pi*(a18)=2*pi*a2*pi*18=2*pi*a36*pi (inchs)
Circumference of larger circle:
2*pi*a (inchs)
Difference betwen ircumference of smaller and large circle:
D=2*pi*a(2*pi*a36pi)=
2*pi*a2*pi*a+36pi=
36*pi (inchs)
D=36*pi (inchs)
1feet=12 inchs
D=(36*pi)=(3*pi)ft
D=(A*pi)
A*pi=3*pi Divide with pi
A=3 
D=(36*pi)in=(3*pi)ft
Respond to this Question
Similar Questions

mathgeometry
The sum of the radii of two concentric circles is 40. A chord with length 36 of the larger circle is trisected by the smaller circle. The area of the smaller circle is k*pi. Find the value of k. Express your answer as an exact decimal. … 
math...2 word problems
Two questions: (1) In a class every boy is friends with exactly 3 girls. Every girl is friends with exactly 2 boys. There are only 19 desks (each holding at most two students), and 31 of the students in the class study French. How … 
Algebra
in a dartboard ther r 2 circles,one large circle n a smaller shaded one inside the larger one. the large circle has a radius of 2 feet n the smaller circle has a diameter of 2 feet. if a dart os thrown at the board wats the probibility … 
Math
(Two concentric circles are shown)The smaller circle's circumference is 10pi. The chord's length is 24. What is the diameter of the larger circle. 
Please help with circle tangents geometry
Two circles of different sizes are tangent at T. A is on the smaller circle, whereas B is on the larger one. Also, segment CD is tangent to the smaller circle, and crosses the goes through the larger circle and hits the other side … 
Math
Jason drew two circles. the diameter of the larger circle is twice the diameter of the smaller circle. What is the ratio of the circumference of the smaller circle to the circumference of the larger circle? 
geometry maths
a circle of radius 1 is inscribed in a square. A smaller circle is tangent to two sides of the square and the first circle. Determine the radius of smaller circle and larger circle 
summer math hw
one circle has a diameter of 10 inches. a second circle has a diameter that is twice the diameter of the first circle What is the ratio of the area of the smaller circle to the larger circle 
apex geometry
Hannah constructed two similar circles as seen in the image below. If the arc length of the larger circle is , which of the following would be true? 
Math
The radius of the larger circle is 9cm. The diameter of the smaller circle is 11cm. Find the area of the shaded region The shaded area is between the larger circle and smaller circle . It is concentric The area of the larger circle …