Not equal to.

Since the height of round cake molds is generally fixed, the formula for calculating the volume of a cylinder is V=π(d/2)^2 *H (base area multiplied by height), so V1: V2= (d1: d2)^2, therefore, 8-inch cake ingredients: 12-inch cake ingredients = (8/12)^2=0.45

That is, to make a 12-inch cake recipe into an 8-inch cake, you need to Multiply its material by 0.45 and that's it.

To convert 12 inches to 8 inches, the material formula is (12/8)^2=2.25 times.

And 8-inch cake: 14-inch cake = (8/14)^2=0.33.

14-inch cake: 8-inch cake=(14/8)^2=3.

Assume that the volume of the 8-inch cake is X, then the volume of the 12-inch cake is 2.25X, and the volume of the 14-inch cake is 3X.

Then the volume of the eight-inch cake plus the 12-inch cake is 3.25X, which is not equal to 3X the volume of the 14-inch cake.

The same is true for the conversion of cakes of other sizes

You can remember this: cakes of different sizes are based on their respective square ratios, which is the proportion of materials.