Originally Posted by dcgator
Math problem: Recipe for cake calls for TWO 9" pans filled with batter. What size pan should I use if I just want one pan of cake?
Trying to keep the amount of ingredients intact. This recipe is from Babbo's Pan di Spagna web site.
Okay I'll assume this is a serious question, and that it's a math problem. I'll assume you want to keep the height the same too.
The area of a circle is pi times the radius squared = 3.14 * 4.5 * 4.5 = 63.6 square inches, or about 127 square inches to account for the two pans used.
You could use any rectangular pan where the length times the width equals about 127 square inches.
I like Charlie's suggestion of 9"x13" which works out to 117 square inches. It seems counter-intuitive that two 9" rounds would almost fit into a 9"x13" but the additional 4x9 inches plus the part you get squaring the circle is almost enough.
Your cake would be 127/117 taller than each 9" round cake portion, about 9 percent taller. You could make some cupcakes if you want exactly the same height.