It kept me very busy in my lunch break
These are the results I got, though again they are very likely a bit off
Rigel
810 light years and 85 solar diametres
810 x 9.4605284 x 10^18
= 7.66 x 10^12
85 x 1.391 x 10^12
= 1.182 x 10^14
19.41/1.182 x 10^14
= 1.642 x 10^-17
7.66 x 10^12 x 1.642 x 10^-17
= 1.257 x 10^14
= 1.257 x 10^8
= 1.25 x 10^2
= 125km
Betelguese
640 light years and 900 solar masses
640 x 9.4605284 x 10^18
= 6.05 x 10^12
900 x 1.391 x 10^12
= 1.251 x 10^7
19.41/1.251 x 10^7
= 1.55 x 10^-10
6.05 x 10^12 x 1.55 x 10^-10
= 9.377 x 10^13
= 9.377 x 10^8
= 9.377 x 10^2
= 937.7km
Sirius
8.64 light years and 1.71 solar diametres
8.64 x 9.4605284 x 10^18
= 8.173 x 10^13
1.71 x 1.391 x 10^12
= 2.378 x 10^12
19.41/2.378 x 10^12
= 8.162 x 10^-13
8.173 x 10^13 x 8.162 x 10^-13
= 6.67 x 10^17
= 6.67 x 10^11
= 6.67 x 10^2
= 667km
Gliese 581
20 light years and 0.36 solar diametres
20 x 9.4605284 x 10^18
= 1.892 x 10^11
0.36 x 1.391 x 10^12
= 5.007 x 10^11
19.41/1.892 x 10^11
= 1.025 x 10^-13
5.007 x 10^11 x 1.025 x 10^-13
= 5.132 x 10^12
= 5.132 x 10^6
= 5.132 x 10^2
= 513.2km
Alpha Cen A
4.395 light years and 1.23 solar diametres
4.395 x 9.4605284 x 10^18
= 4.157 x 10^13
1.23 x 1.391 x 10^12
= 1.710 x 10^12
19.41/1.710 x 10^12
= 1.135 x 10^-14
4.157 x 10^13 x 1.135 x 10^-14
= 4.718 x 10^14
= 4.718 x 10^8
= 4.718 x 10^2
= 471.8km
...maybe? I think I'm on the right track but so far I seem to get something wrong
