lab assumes knowledge of trigonometry

[kthffmn]

Frontmatter should include what the following types of triangles are:

:triangular_ruler: :triangular_ruler: :triangular_ruler::triangular_ruler: :triangular_ruler: :triangular_ruler:

• scalene
• equilateral
• isosceles

It should also include info on what makes an impossible/illegal triangle (impossible sides (negative sides), inequality rule).

[AnnJohn]

Iceboxing for now