British flag theorem (Rectangles)
Little's Law
Bradley model of the force applied on a contact area between two spheres
Maximum axial load that a long, slender, ideal column can carry without buckling
Area of a Square
Johnson-Kendall-Roberts (JKR) model of elastic contact between two spheres ( pull-off force)
Area of rhombus (by diagonals)
Tangent of the difference of two angles (Bhāskara formula)
Terrestrial Time