Solving the Mystery of the Biblical Flood II

Before the Great Flood the Lord told Noah:
"So make yourself an ark of cypress wood; make rooms in it and coat it with pitch inside and out.This is how you are to build it:The ark is to be 300 cubits long,50 cubits wide and 30 cubits high.Make a roof for it and finish the ark to within 1 Cubit of the top."(Gen.6,14-16)Sacred Cubit (the cubit of old standard 2 Chron.3,3)= 63,5 cm = 25 inches.The Capacity of these measurements(300x50x30 SC)with the roof part of the Ark = 7.148.437.500 cubic inches = 117.141.987,5 liters.Specific gravity of cypress wood = 0,51 g/cm3.The total volume of the Noah's ark with the specific gravity of cypress wood gives a number of 59.742.413,6 kg
Earth weights 5974241360000000000000000 kgAccording to the Great Pyramid the mean size of Earth = 40017,93119 km,and its mean volume gives 108221522000km3.
59742413600 : 108221522000 = 5,5203819944
Earth's pecific gravity = 5,520381944

Please show the details of this calculation since a volume of 300 * 50 * 30 doesn't give the answer you supply. What is the "roof part"?
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The roof = prism: a)length = 300 cubits(sacred cubits) = 7500 inches
b)width = 50 cubits = 1250 inches
c)height = 1 cubit = 25 inchesVolume = (7500 x 1250 x 25): 2 = 117187500 cub. inches = 1920360,45 liters (+ volume of the Ark).