Most basic formulae for surface area can be obtained by cutting surfaces and flattening them out.

This formula is obtained by counting how many times a given permutation shape can occur.

He made clear how the dye formula of the Beecher brothers had been obtained.

But the formula must be obtained for the Yanks just the same.

Explicit formulae for the overall elastic constants have not been obtained, however, by the method.

The molecular formula has not been obtained for canavesite.

The formula can be obtained by use of dimensional analysis.

Heron's formula is obtained by setting the smaller parallel side to zero.

Both formulas are obtained by inversion of the cdf.

The next sections describe how these formulas may be obtained.