[Woodcarver] Thirteen Point Star

[Edward Cusson]

Thirteen Point Star:

           To create a thirteen point star. Construct a circle whose 
circumference is 13 inches.  This is a circle of radius 2.069 
inches.   Recall that dividers are set to the chord length not the arc 
length.  So to step off 13 one-inch points along this circumference one 
needs to calculate the length of the chord whose radius is 2.069 inches and 
whose included angle is 27.692 degrees. To set the dividers to properly 
step off thirteen points one must use the law of the cosines to calculate 
the chord length . Using a radius of 2.069 inches and an included angle of 
27.692 degree leads to a chord length of .981 inches.  Set your dividers to 
this length and now you can step off exactly thirteen points along the 
circumference.  To generate different star sizes project rays from the 
center through the points along the circumference to any desired length and 
draw a new circle for the required size and connect the points to form the 
wanted star.   Hope that this helps.

Ed