geometry

• December 21st 2009, 12:31 AM
uma
geometry
Two circles have diameters in the ratio 1:3. Find the ratio of their circumferences.
• December 21st 2009, 01:53 AM
Hello uma
Quote:

Originally Posted by uma
Two circles have diameters in the ratio 1:3. Find the ratio of their circumferences.

The ratio of any two corresponding lengths of two similar figures will be the same, no matter which two corresponding lengths are chosen. So if the diameters are in the ratio 1:3, the circumferences will also be in the ratio 1:3.

(Note, though, that the areas will be in the square of this ratio; so they'll be in the ratio 1:9.)

circumference= $\pi d$ and since pi is a constant so the circumference depends entirely on its diameter .