Calculation: zia3on - 1

V  = 
 
 1
/ 3
* h* (S1+S2+saknis( S1* S2))
V =  
 1
/ 3
* h* (S1+S2+saknis( S1* S2))
$$V$$ = $$\frac{1}{3}\cdot h\cdot (S1+S2+\sqrt {S1\cdot S2})$$
V =  
 S1* h
/ 3
+ 
 S2* h
/ 3
+ 
 saknis( S1* S2)* h
/ 3
$$V$$ = $$\frac{S1\cdot h}{3}+\frac{S2\cdot h}{3}+\frac{\sqrt {S1\cdot S2}\cdot h}{3}$$
V =  0.33333* S1* h+ 0.33333* S2* h+ 0.33333* h* saknis( S1* S2)$$V$$ = $$0.33333\cdot S1\cdot h+0.33333\cdot S2\cdot h+0.33333\cdot h\cdot \sqrt {S1\cdot S2}$$