Pythagoras' Big Theorem
Square of the area of the largest face
= areaPQR**2
= (1/4)H**2B**2
= (1/4)(h**2+b**2)(a**2+c**2) [Pythagoras' Theorem]
= (1/4)((ac/B)**2+b**2)(a**2+c**2) [Similar Triangles]
= (1/4)((ac)**2+(ba)**2+(cb)**2)
= areaOPQ**2+areaOQR**2+areaORP**2
= Sum of the squares of the areas of the 3 smaller faces of a right tetrahedron