Question

How to i find a ratio

Answer 1

Its half of the diameter which is the measure of a straight line passing through each side of a circle. So if a diameter is 12 then the ratio is like 6.

Answer 2

USE MULTIPLICATION OR DIVISION TO "SCALE" RATIOS
1.For example, a baker needs to triple the size of a cake recipe. If the normal ratio of flour to sugar is 2 to 1 (2 : 1), then both numbers must be increased by a factor of three. ...
2.The same process can be reversed.