In a right triangle, if one angle is 30 degrees and the hypotenuse is 10, what is the length of the side opposite the 30-degree angle?

In a right triangle with one angle measuring 30 degrees, the lengths of the sides can be determined using the properties of a 30-60-90 triangle. In such a triangle, the side opposite the 30-degree angle is half the length of the hypotenuse.

Since the hypotenuse is given as 10, the length of the side opposite the 30-degree angle is calculated as follows:

[

\text{Length of the side opposite 30 degrees} = \frac{1}{2} \times \text{hypotenuse} = \frac{1}{2} \times 10 = 5.

]

Thus, the correct answer is 5, confirming that the length of the side opposite the 30-degree angle is indeed 5. This property is fundamental in trigonometry and is crucial for solving problems involving right triangles.