None. Neither a tennis ball, nor tennis, are essential to human survival. There is no "use".
The biggest globe in the world is in France. Made in 1824. Diameter of 128 feet (39 meters.)
On May 17, 2003, the record was set for world's largest cookie. It weighed 40,000 lbs. and had a diameter of 101 ft.
Circumference of a circle divided by pi is equal to the circle's diameter.
pi = circumference/diameter
The biggest pancake ever made was over 49 feet in diameter and weighed over 6,600 pounds. It was cooked in Rochdale, Greater Manchester, UK in 1994. So yeah, that pancake could probably feed a small village or serve as a makeshift trampoline for a bear.
The diameter of a circle is twice its radius and spans the circle passing through its centre.
The tallest pencil in the world is located in Subang Jaya, a suburb in Selangor, Malaysia. It stands at 19.75 m long with a 0.8 diameter. Made out of actual wood, it's placed inside it's own glass house in the Faber Castell building.
Diameter of ring=34.1/3.414=9.9cm ( approx 10 cm)
The world's biggest Christmas pudding weighed around 7,231 pounds and was made in the UK in 1992. It measured over 15 feet in diameter and took over 12 hours to cook.
the mega-mini pizza of the moon your mother
The smallest coin ever produced for circulation by the Royal Mint was 11mm in diameter. The British Halfcrown coin was 32mm in diameter and weighed 14.1 to 14.14 grams when it was made from silver and 14.2 grams when it was made from cupro-nickel.
A diameter is made up of 2 equal radius, so it would be 2 x .9 or 1.8