Question 15708
The measure of the circumference of a circle (also a wheel) is given by:
{{{C = (pi)D}}} or, if you know the radius, {{{C = 2(pi)r}}} since D = 2r.

You want to find the radius, so use:
{{{C = 2(pi)r}}} and solve this for r. Divide both sides by {{{2(pi)}}}
{{{r = C/2(pi)}}} Substitute 42" for C and 3.14 for {{{(pi)}}}
{{{r = 42/2(3.14)}}}
{{{r = 6.687898}}} Round to nearest 1/100th

r = 6.69 inches.

Each spoke is 6.69 inches