Question

Why we muliply when we renove symbol of propartionality?

Answer 1

Hey

Here is ur answer !

A is proportional to B can indicate two things. 1) as A increases, B also increases 2) as A increases, B decreases 
Each proportionality is termed as direct proportionality(ABAB is constant) and inverse proportionality(A×BA×B is constant) respectively. The increase and decrease is by a single factor. Like ππ
Perimeter(P) and diameter(d) of a circle are directly proportional(when diameter is stretched out, proportionally perimeter get stretched to preserve the circular shape) Ie, PαdPαd
Formula for perimeter is:
P=π∗dP=π∗d
See the proportionality sign is replaced by the constant π