Homework Help: math

Posted by dan on Tuesday, March 15, 2011 at 12:09am.

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.

math - Anonymous, Tuesday, March 15, 2011 at 12:58am
Radius of smaller circle: a-18 (inchs)

Radius of larger circle: a (inchs)

Circumference of smaller circle:
2*pi*(a-18)=2*pi*a-2*pi*18=2*pi*a-36*pi (inchs)

Circumference of larger circle:
2*pi*a (inchs)

Difference betwen ircumference of smaller and large circle:

D=2*pi*a-(2*pi*a-36pi)=
2*pi*a-2*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
math - Anonymous, Tuesday, March 15, 2011 at 1:00am
D=(36*pi)in=(3*pi)ft

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