In the above graph absolute brightness is marked on y-axis and surface temperature is marked on x-axis.
To find out what type of star has an absolute brightness of 5 and a surface temperature around 3,000 °C, we will draw a straight line from x axis which represents a temperature of 3,000 °C and another straight line from y-axis which represents absolute brightness of 5.
From the attached graph we can see that these 2 lines meet in the region shown by Supergiants
Therefore we can say that, Supergiants has an absolute brightness of 5 and a surface temperature around 3,000 °C
