#### Answer

109.4 degrees

#### Work Step by Step

Since we are given that it is a tetrahedral shape, we can solve for delta 0.
Delta 0 = 180-90-tan$\frac{1}{\sqrt 2}$
= 180 - 90 - 35.2 = 54.7.
However this is only half the angle. Therefore, we must mutiply it by two to get the whole angle.
2 $\times$ 54.7 = 109.4 degrees