Find Side AC in Right Triangle ABC with Sides of 3 and 10

To find the length of side $AC$ in the right triangle $\triangle ABC$, we'll use the Pythagorean Theorem:

• Step 1: Identify the given sides. Side $AB = 3$, and hypotenuse $BC = 10$.
• Step 2: Apply the Pythagorean Theorem: $AC^2 = AB^2 + BC^2$.
• Step 3: Substitute the known values: $AC^2 = 3^2 + 10^2 = 9 + 100 = 109$.
• Step 4: Solve for $AC$: $AC = \sqrt{109}$.

Upon calculating, we find that the length of $AC$ is $\sqrt{109}$.

This length corresponds to choice 3 from the provided options.

Thus, the solution to this problem is $AC = \sqrt{109}$.