Hypergiants are super luminous supergiants. It isn't all about sheer size. Eta Carinae is a hypergiant but it is smaller than the supergiant Antares. This is due to the fact that Eta Carinae is about 60 times as luminous as Antares and 10 times as massive. Although size doesn't matter, the largest star VY Canis Majoris is a Hypergiant.
the super giant stars are red
Hypergiant.
The star Betelgeuse is a supergiant.
Main Sequence stars can be any spectral class of star. Something that might help you in the future is when you look up a star and see its spectral class, its always followed by a roman numeral to define where the star is in its life and size and they go as follows. I-a= A hyper Giant Star I-b= A very bright Super Giant star I= A normal Super Giant star II= Bright Giant star III= Giant star IV= Sub Giant star V= Dwarf Star(which this is where most main sequence stars fall into, While a main sequence star could also be one of the classifications listed above. it just depends on its spectral class. for example the star Deneb is in its main sequence still and its classified as a hyper giant) VI= Sub Dwarfs (this is a very rare classification and are mostly used for brown dwarfs. I hope this helps mate.
Blue when it is young and red just before it dies.
first its called the main sequence star like the sun then it becomes a red giant then it becomes a red super giant and if it is huge a hyper-giant like VY Canis Majoris (largest star known) then it explodes and it becomes a planetary nebula then it becomes a white dwarf
that depends on how large the red or super red giant was. if it was a super red giant that is 1000X larger than a red giant. it will become a black hole
The giant star
A star is considered "dead" when nuclear fusion stops in its core. The name of the a star before this happens depends on its size. If its a star the size of our own, Sol, then it will be called a red giant. If it is considerably lager then it will be called either a giant, bright giant, super giant or hyper giant. This again depends on its size.
Antares
VV Cephei
Their mass. If its mass is nearly like of sun it will become red giant. If its much bigger, it will become super giant
the super giant stars are red
Cygnus ob2 no.12, a hyper star is & also the biggest.
Hypergiant.
The sun is a star itself. The sun is actually a very small star. There are stars that are WAY bigger then the sun.Like the VY Canis majoris star. The sun is invisible compared to that super giant star.
A giant star is smaller than the sun.