Part 1: Describe the mass and the surface temperature of the giant stars.

Part 2: Explain using complete sentences where on the HR diagram you would expect to find a giant star based on its physical properties.

1) A giant star is a star with a radius much larger than that of our Sun (even hundreds of times bigger). They can be either blue giants or red giants: in the first case, the surface temperature is very high, higher than that of the Sun, while in the second case the surface temperature can be lower than that of the Sun. The same applies to the mass: blue giants are very massive stars, burning quickly their nuclear fuel, while red giants can have small masses (a little bit bigger than that of our Sun).

2) We can find giant stars in the upper part of the HR diagram, blue giants will be on the upper left corner since they have high luminosity and high temperature, while red giants will be on the upper right corner, having high luminosity but low temperature.