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Umbrellas

Unit of Measurement	Inches	mm
A. Radius (?) One half of the umbrella's fabric diameter -- measure over a rib from one edge to the center point. Close		inches
B. Number of Gores (?) The number of triangular pie shaped panels with seams radiating from the center (often 8 as in the image above and never less than 3). Close		3 to 20
Hem (?) Finished width of the doubled hem all round the Umbrella. A one inch hem would add two inches of fabric to the length of each gore. This will be zero if a binding is used to finish the circumference of the umbrella. Close		inches
C. Open Diameter (?) Measure the diameter of the opened umbrella if possible. This diameter will normally be roughly 10% less than twice the radius measured above. This measurement determines the shape of the umbrella "cone". Close		inches
Fabric Width (?) Actual width of fabric (often 46, 54, or 60 inches -- 1168, 1372, and 1524 mm) Close		inches

Vent with Fly:
Yes (?) A 16 inch opening will be provided at the center with a 28 inch circular fly to cover it. Close	No (?) There will be no hole at the umbrella's center. Close

NOTE: Our goal is to make the Fabric Calculator as accurate as possible, but please double-check all results thoroughly. Sailrite will not be held responsible for any miscalculations, cut fabric, or purchased fabric as a result of this software.