The relationship between a star's radius and mass is not linear, meaning a bigger mass doesn't automatically mean a bigger radius. It's more complex and depends on the star's evolutionary stage and its internal structure.

Here's a breakdown:

* Main Sequence Stars: These are the most common type of stars, fusing hydrogen into helium in their core. Their radius is roughly proportional to the cube root of their mass. This means that a star twice as massive as the Sun will have a radius about 1.26 times larger.

* Giant Stars: As stars age and exhaust their hydrogen fuel, they expand significantly, becoming giants. Their radius can increase dramatically, becoming hundreds of times larger than their main sequence radius even though their mass might not have changed much.

* Supergiants: These are the largest stars, and their radius can reach thousands of times the Sun's radius. Their mass, however, can range from a few to several dozen times the Sun's mass.

Here's a key point to remember:

* Massive stars burn their fuel faster and have shorter lifespans. This means that while a massive star starts with a larger radius than a smaller star, it will reach the giant and supergiant phases much faster.

Example:

* A star with 10 times the Sun's mass will be about 2.2 times larger than the Sun (10^(1/3) ≈ 2.2). However, when it becomes a red giant, its radius could be hundreds of times larger than the Sun even though its mass remains roughly the same.

In conclusion, there's no simple, direct relationship between a star's radius and mass. It depends on factors like its age, evolutionary stage, and internal structure.