a pyramid, in the sense that most people think of has a square base, with 4 triangle 'sides', which would be 5 faces. A regular tetrahedron has 4 equilateral triangles as faces.
an equilateral triangle has all its angle and sides equal
A pentagonal pyramid.
An octohedron, or diamond
an equalatural triangle is a triangle ( 3 sided figure) that has all equal sides.
The definition of a scalene triangle is: A three-sided figure (triangle) with no two sides equal.
It is an equilateral triangle that has 3 equal sides.