Area of circular pan: pi*9 squared = 254.469 square inches Area of square pan: 18*18 = 324 square inches which has the greater area
To get the area of a square (including rectangles), multiply side (12) x side (9), which equals 108 inches.
A 9x13 pan has a much greater volume than a round cake pan... if you need to use round pans you would probably be better off substituting two 9' round pans for one 9x13' pan. Ex.: The volume of a 9x13 pan is 9*13*1.5 = 175.5 Volume of a 9' round pan is 3.14*4.52*1.5 = 95 So a 9' round pan will hold about half the batter of a 9x13' pan.
The best and most popular type of pan used for double layered cakes is a round pan that is 9 inches across.
The only difference is the size (diameter) of the pan.
It depends on how deep the pan is.
The volume of the batter is the same. Volume in the 6 in pan: Pi r2 h = 18Pi . Volume in the 8 in pan: 16hPi . Equating the two: 18Pi = 16hPi gives h = 9/8 in.
The area of a rectangle that is 7 inches by 9 inches is 63 inches squared.
117 square inches (13 x 9 = 117)
The area of a circle with a diameter of 9 inches is: 63.62 square inches.
A eight by eight pan would have an area of 64. So a pan double that size would have an area of 128. Therefore we need a pan that length and width multiply to equal 128. This can mean a 8 by 16 or 11.3 by 11.3 pan. In standard bakeware, a 9 X 13 pan can be used to double a recipe that calls for an 8 X 8 pan.
9 x 12 = an area of 108 square inches