To find the moment of inertia of a square section about an axis formed
by one of its diagonals (I = (_s_^4)/(12)).
Set index of C to the length of the side of square _s_ on D; bring
cursor to _s_ on C, 12 on B to cursor, and over index of B read moment
of inertia on A.
To find the moment of inertia of a rectangular section about an axis
parallel to one side and perpendicular to the plane of bending.
Set index of C to the height or depth _h_ of the section, and bring
cursor to _h_ on B. Set 12 on B to cursor, and over breadth _b_ of the
section on B read moment of inertia on A.
EX.—Find the moment of inertia of a rectangular section of which _h_ =
14 in. and _b_ = 7 in.
Set index of C to 14 on D, and cursor to 14 on B. Bring 12 on B to
cursor, and over 7 on B read 1600 on A.