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# how to calculate a spiral arch?

How do I figure out the approximate number of balloons to make a spiral arch?

### Comments for how to calculate a spiral arch?

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 Rating Balloon calculation NEW by: Anonymous i am confused with these calculation please explain.

 Rating 4 balloon cluster spiral arch NEW by: Anonymous Calculate 16"/41cm balloons. Inflated to a 15"/38cm diameter , required to make a 4 balloon cluster spiral arch with as base width of 30'/9.15m and height of 18'/5.5m

 Rating How to calculate number of balloons for spiral arch by: Margit Hi Sharon, As your arch is wider than it's tall, you need to add width plus height to get the approximate length, as explained at our balloon arch instructions page. Arch length: 610cm + 370cm = 980cm Number of balloons, according to Bruce Walden's formula below: 980cm / 27cm * 4.8 = 174.2 balloons Number of 4-balloon clusters: 174.2 / 4 = 43.6 As Sean said in his helpful post below, you'll have to decide if you want to make 43 or 44 clusters. This means you'll need between 172 and 176 11" balloons.

 Rating cluster spiral arch by: sharon how to calculate a number of 11'/28cm balloons, infated to a 10.5"/27cm diameter required to make a 4-balloon cluster spiral arch with a base width of 20'/6.1m and a height of 12'/3.7m. please show it

 Rating Calculating the No of Balloons in a Garland by: Anonymous The first thing you have to do is calculate the length of the Arch. eg; 2 x H + W once you know the length the rest is basically easy thanks to the pioneering brain power of Bruce Walden. Calculating The Number of Balloons In A Garland If the length of the garland and the diameter of balloons are in the same units (both in ft, in, m, cm, mm ) divide the diameter of the balloon into the length of the garland and multiple by 4.8 to get the number of balloons needed for a 4-pack "spiral" garland. Length of garland (unit) -------------------------------- x 4.8 = # of balloons Diameter of balloon (same unit) Example Using a 4 x Balloon Cluster Garland: [A 304.8 cm long garland (10 ft) made from 25.4 cm balloons (10in)] Therefore 304.8 divided by 25.4 = 12 x 4.8 = 57.6 balloons 57.6 balloons when divided by 4 to calculate the number of Clusters = 14.4 Clusters Because you can not use .4 of a balloon you will have to decide if you want to use 14 or 15 Clusters of 4 balloons each inflated to 25.4 cm (10inches). Exact final result can slightly vary according to tightness of packing of each individual Cluster. Maths formula for calculating the number of balloons in a Garland using metric measurements kindly provided by Bruce Walden (Toronto, Canada) Sean O'Kelly Balloon Decor.com.au Australia

 Rating Calculate by: Anonymous If you are using 11" balloons with 4 in a cluster.... multiply feet x 6