SOS APPENDIX CALCULATION OF THE 



THE REGULAR TETRAHEDRON. 

 Fig. 332. 



Its elements. 



The mutual inclination of any two adjacent planes 

 at their common edge zz 70 31' 44", and may 

 be called /,. 



Plane angles zz 60, and may be denoted by A t . 

 Edges all equal. 



Inclination of an edge a do a perpendicular, 

 a b = 54 44' 8", and may be called A 2 . 

 Inclination of an edge to an axis zz 35 15' 52", 

 and may be called A 3 . 



Inclination of a perpendicular a b to an axis 

 zz 19 28' 16", and may be called A 4 . 

 Ratio of a perpendicular 

 a b : an edge a c : : ^3 ' 2. 



Its units of comparison. 



Vg 

 The unit is zz , in relation to simple or mixed 



decrements on the angles. 



. . . . zz 1, in relation to decrements on the 

 edges. 



