Can you assume a tetrahedron is regular without specification?

[Matejxx1]

We were writting a test on wednessday and for the first question we were asked to calculate the angles of the base of a tetrahedron with points A,B,C,D. ABC being its base. We were also given some relation which helped me calculate that the base of the tetrahedron is an equilateral triangle which meant that all of the angles were pi/3.

However when i spoke to some of my classmates most of then just wrote that a tetrahedron is composed of 4 equilateral triangels so that means that the anglrs are all pi/3.

Can you really do that taking into account that the question didn't specify that the tetrahedron was regular .
Thanks

 

[andrewkirk]

Not all tetrahedrons are regular, and not even all tetrahedrons with equilateral bases are regular. So it is incorrect to say that a tetrahedron is composed of four equilateral triangles if one has not been told that it is regular.