Creating precise arcs
The Measurements Toolbar displays the chord length of the arc (after setting the starting point), then the bulge distance (after setting the ending point). Use the Measurements Toolbar to enter exact lengths for the chord length, bulge distance, radius value, and number of segments.
Entering a chord length
The Measurements Toolbar's label indicates 'Length' after you place the starting point of an arc. Type the chord length into the Measurements Toolbar, after placing the starting point of the arc, and press the Enter (Microsoft Windows) or Return (Mac OSX) key. Specify a negative value, such as -6.5", to indicate that you want the length to apply in an opposite direction to the current drawing direction.
Specifying a bulge distance
The Measurements Toolbar's label indicates 'Bulge' after you place the ending point of an arc. Type the bulge length in the Measurements Toolbar, after placing an ending point, and press the Enter (Microsoft Windows) or Return (Mac OS X) key. You can also enter the bulge distance after the creation of the arc as long as 'Bulge' is displayed as the Measurements Toolbar label. Negative bulge values can also be used to create an arc in an opposite direction to the current drawing direction.
Specifying a radius
You can specify an arc radius instead of a bulge distance. Type the desired radius in the Measurements Toolbar, followed by the letter r and press the Enter (Microsoft Windows) or Return (Mac OS X) Key. You can perform this action either during or immediately following the creation of the arc. For example: 24r or 3'6"r or 5mr.
Specifying the number of segments
You can also specify the number of segments in an arc. Type the number of segments in the Measurements Toolbar, followed by the letter s, and press the Enter (Microsoft Windows) or Return (Mac OS X) key. You can perform this action either during or immediately following the creation of the arc. For example: 20s.