\shadowbox{Joone  \; y=f(x) \; pööramisel \; ümber \;x-telje\;rajades \ 
 x=a \; kuni \; x=b \; saame\;pöördkeha\;ruumala\
V= π \int_{a}^{b}{ f\left(  x \right)^2 dx  }.}

Pirni ruumala määramine integraali abil

\fbox{Veega \;  ääreni \;  täidetud \;nõu  \; kaal: 1237  \;g.\
Veega \; osaliselt \; täidetud \; nõu\; \; kaal \;peale\
 pirni \; väjavõtmist: 1030 \; g.\
Pirni \; poolt \; väljatõrjutud \; vee \; kaal: \; 207 \; g. }

A = (0, -3.8120934545454546)
B = (8.1, -3.8120934545454546)
D = (0.5025914360562469, 2.393820823049596)
E = (1.4200039523433816, 3.2302851761349247)
F = (2.4723300739668597, 3.617037511432442)
G = (3.9383912519551236, 3.4821239060960987)
H = (4.927757691088307, 3.2662621375579493)
I = (5.4764063527894375, 2.798561639058626)
J = (5.845170207375443, 2.1869532948672026)
K = (6.01606077413481, 2.043045449175103)
L = (6.591692156903209, 1.9171260841945161)
M = (7.068386895758288, 1.6383046331660733)
N = (7.608041317103662, 1.2515522978685556)
C: (0, 0.8)
O: (8, 0.819)
f = Fit({C, D, E, F, G, H, I, J, L, K, M, N, O}, {1, x, x^(2), x^(3), x^(4), x^(5), x^(6), x^(7), x^(8)})
text2: "f\left( x  \right) = \; " + (LaTeX[f]) + ""
V: (π * Integral[f(x)^(2), 0, 8])
V_{ligikaudne}: round(V)
text3: "Antud\;pirni\; puhul\;V= π \int_{0}^{8}{ f\left( x \right)  ^2 dx}≈" + (LaTeX[V_{ligikaudne}]) + "\;cm^3."