EN  
you are here.
  Home  > 
blog
 > 
how many onions should I cut


How many onions should I cut

1 large onion equals 8 small ones

September 1, 2019,  | 
Often we can't imagine how many small onions we should cut instead of the big one. Luckily, we can calculate this using a simple three-dimensional sphere volume formula. Suppose we have a large onion that has each of 3 dimensions twice the size of the small one. If the radius r is, for example, 2 cm, then the radius of the large onion 2r is 4 cm. The volume of a large sphere is always 8 times greater than the volume of a sphere with a half radius r.
V1 = 4 / 3 ˣ π ˣ (2r)3 V2 = 4 / 3 ˣ π ˣ r3
V1 = 4 / 3 ˣ 3,14 ˣ (4 cm)3 V2 = 4 / 3 ˣ 3,14 ˣ (2 cm)3
V1 = 4,19 ˣ 64 cm3 V2 = 4,19 ˣ 8 cm3

V1:
Volume of sphere / large onion
V2:
Volume of sphere / small onion
r1: 2r
- Radius of a large onion
r2: r
- Radius of a small onion
π: 3,14
- Ludolf's number

V1 = 4 / 3 ˣ 3,14 ˣ 2r ˣ 2r ˣ 2r
V2 = 4 / 3 ˣ 3,14 ˣ r ˣ r ˣ r

V1 = 4,19 ˣ 8r3
V2 = 4,19 ˣ r3

V1 = 8 ˣ V2
Simplified view
By accessing vla.sk pages, you agree to abide by 
Terms and conditions of use.
Terms and conditions of use  |  Sitemap
Copyright © 2007-2019
Vladimír Slávik