Length Question

Decorating By dreamtreats Updated 10 Jun 2010 , 5:56pm by mpetty

 dreamtreats  Cake Central Cake Decorator Profile
dreamtreats Posted 10 Jun 2010 , 5:31pm
post #1 of 7

I seem to have math issues when trying to figure out how long to roll out fondant when cutting a stripe for cakes.

So heres what I need:
If i have an 8" cake how long should a 'ribbon base' be?
6" cake?
and so on? Never get it right and me a seams dont get along.

6 replies
 CrazyCatLady  Cake Central Cake Decorator Profile
CrazyCatLady Posted 10 Jun 2010 , 5:43pm
post #2 of 7

pi X diameter = circumference

so:

3.14 X 8" = 25.12"

3.14 x 6" = 18.84"

just multiply whatever size the cake is times 3.14 (pi).

 jqorso  Cake Central Cake Decorator Profile
jqorso Posted 10 Jun 2010 , 5:45pm
post #3 of 7

For round cakes:

C=PI*D

Where D is the diameter of the cake and PI = 3.14 (it's enough sig figs for cake).

So for an 8" cake you need a minimum of 25.12 inches (8"*3.14). Round up though to make sure you have wiggle room for extra frosting and such. It's better to have too much than not enough.

 carolyn1489  Cake Central Cake Decorator Profile
carolyn1489 Posted 10 Jun 2010 , 5:47pm
post #4 of 7

Im a big math nerd so....

The length you need is the circumference of the circle, which is just a measurement around the circle.

The equation for it is d(diameter)*pi

Diameter is easy, that is the size of your cake pan=8inches

Pi is 3.14

Just multiply the 2= 25.12 inches

To be on the safe side, always add a few more inches!

For your second cake, you need 18.84 inches.

Hope that helps!

 robyndmy  Cake Central Cake Decorator Profile
robyndmy Posted 10 Jun 2010 , 5:49pm
post #5 of 7

I'm terrible at math myself, so I always just keep a sewer's measuring tape in the kitchen (those flexible ones). Comes in handy for things just like that, length, amount of rolled fondant I need, etc. HTH!

 melmar02  Cake Central Cake Decorator Profile
melmar02 Posted 10 Jun 2010 , 5:50pm
post #6 of 7

Sorry to hijack, but some of my co-workers were just talking about how they never use math in our job or their lives. I piped up and said I use geometry and algebra all the time for cakes. They were a little in awe that I knew how to find the volume of my cake pans and could convert it to the number of batches of cake I need for each one using ratios. That was the "made me feel smart" moment of the day.


Dreamtreats - you can also measure around your cake with a flexible tape measure or string and roll your fondant out to that length.

 mpetty  Cake Central Cake Decorator Profile
mpetty Posted 10 Jun 2010 , 5:56pm
post #7 of 7
Quote:
Originally Posted by melmar02

I piped up and said I use geometry and algebra all the time for cakes.




LOL, which is why, now that I'm doing cakes, I keep kicking myself for not paying attention in Math class!

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