1. I assume that the vertex of the pyramid is vertically above the center M of the equilateral triangle. (In an equilateral triangle the orthocenter, the centroid, the common point of the three angle bisectors,... is the same point which I call here the center of the triangle)

2. The point M lies on the median through B. The distance

The length of the median is

Thus

3. Now use Pythgorean theorem to calculate

Since VB = 10 the pyramid is a tetrahedron.

4. I'll leave the rest for you.