Wednesday, July 29, 2015

Circumference of circle is 3 times circum. of a smaller circle. If the area of the larger circle is 486 in^2, what is the area of smaller circle?

Let the small circumference be C1 and the larger
circumference be C2.


Given that C2 = 3*C1
........(1)


Given the area of the larger circle is
486


==> A2 = 486


We
need to find the area of the smaller circle.


==> A2
= 486 = r2^2 * pi


==> r2^2 = 486/pi =
154.7


==> r2=
12.44


==> C2 = 2*pi*r =
78.15


But C2 = 3C1


==>
C1 = 78.15/3 = 26.05


==>  C1 = 2*pi * r1 =
26.05


==> r1 = 26.05/2pi =
4.15


==> A1 = r^2 * pi = 4.15^2 * pi =
54


Then the area of the smaller circle is 54
in^2.

No comments:

Post a Comment

What accomplishments did Bill Clinton have as president?

Of course, Bill Clinton's presidency will be most clearly remembered for the fact that he was only the second president ever...