ElectricPavlov

PI  r^2 = area     area of each slice is proprtional @  15degrees/360degrees

pi r^2  x  15/360 = 13.089 ~ 13 sq in

1 You'll have to calculate the volume of the individual pieces and then add them together. 

2  SOMEtimes Calculus can help solve these problems

3 A displacement tank......put the volume underwater and see how much fluid is displaced

4 If possible, see how much volume of fluid the object will HOLD

Not sure what you are asking, but maybe this?

t= 2 pi (w/gf)^2      solve for ' f '

t/(2pi)  = (w/gf)^2

sqrt (t/(2pi))  = w/gf

f = w/ ( g sqrt(t/(2pi)) )       Is that what you wanted?

sqrt 72   - sqrt8  + sqrt 128

sqrt ( 36*2)  - sqrt (4*2) + sqrt (64*2)

6 sqrt 2   - 2 sqrt 2 + 8 sqrt2

12 sqrt 2

Yes , they are equal:

2ab /(b-a)    x  -1/-1    =  -2ab/-(b-a)  =   -2ab/ (a-b)

a^6b^5    is all you can say without more information.....sorry

4 with 13 zeroes after it      4 0, 000, 000, 000, 000      40 trillion

= (6 + 5 -2) (xyz)  = 9 xyz