<Formula>
<-V>
(a^2*h1^2)/(4*(h1+h2+h3+h4))
</-V>
<+V>
(a^2*(h2+h3+h4)^2)/(4*(h1+h2+h3+h4))
</+V>
</Formula>

<Formula>
<-V>
(b*c*h1)/6
</-V>
<+V>
(a^2-b*c/2)*((h2+h3+h4)/5)
</+V>
</Formula>


<Formula>
<-V>
(a^2/6)*(h1^3/((h2+h1)*(h4+h1)))
</-V>
<+V>
(a^2/6)*(2*h2+h3+2*h4-h1)+(a^2/6)*(h1^3/((h2+h1)*(h4+h1)))
</+V>
</Formula>