The main purpose of this note is to illustrate how the radius in
a finite-dimensional power-associative algebra over a field F,
either R or C, may change when the multiplication in this
algebra is modified. Our point of departure will be Fn×n, the
familiar algebra of n×n matrices over F with the usual matrix
operations, where it is known that the radius is the classical
spectral radius. We shall alter the multiplication in Fn×n in
three different ways and compute, in each case, the radius in
the resulting algebra