The Relationship between Angle and Side Opposite is pretty straightforward. As the angle gets bigger, the opposite side does as well. As it gets smaller, the opposite side gets smaller too. See below, kindly.

Even within a triangle, this relationship holds. A triangle of course consists of three angles. The angle opposite the longest side will be the largest, the angle opposite the second longest side will be the second largest, and the angle opposite the smallest side will be the smallest. See below, if you will.

WARNING: This relationship is NOT proportional. For example, notice that the side opposite angle $b$ is $10$ and the side opposite angle $c$ is $5$. Does this mean that angle $b$ is twice as large as $c$? Nope! The relationship doesn't work like that. They're not that close.