If this is a real-life question it can't be answered, as real rims and hubs have all kinds of shapes to them that mess up the measurements. IRL a spoke wouldn't reach all the way to the center for instance, it'd be attached some way off, at the hub flange. You'd also need to know what lace pattern is being used, as that affects spoke length. But if this was a maths question that isn't required to make sense then spoke length would be (42/pi)/2.
The area of a circle with a circumference of forty two units is 140.4 square inches.
A circumference of 125.66 feet.
Forty thousand kilometres
diameter = circumference/pi = 40/3.1416 units = 12.73 units (approx)
there are about 12 cm in forty-one inches
Forty inches.
One yard is 36 inches. So, forty inches is 1 1/9 yards.
231 cubic inches = 1 gallon 48x48x72= 165,888 cubic inches 165888/231=718.13 gallons
1,811,000,000,000 inches.
16.8 inches
45 inches is 1143mm
1440