Hello,
I have a recipe for a cake which requires 100gm of flour and 100gms of
butter and two 7" pans. If i change it to a 9" pan, do i
a) multiply the weights of flour and butter by 9/7?
or
b) multiply by ratio of areas i.e multiply by 81/49 (9^2/7^2) ?

Thank you for your time
Saptarshi