OpenSAT

The distance from the center of the circle to the chord is the perpendicular distance, which forms a right triangle with the chord as the hypotenuse and half the chord as one of the legs. Since the chord is 8 units long, half the chord is 4 units long. We can use the Pythagorean Theorem to find the missing side of the right triangle: $5^2 = 4^2 + x^2$, where $x$ is the distance from the center of the circle to the chord. Simplifying the equation, we get $25 = 16 + x^2$. Subtracting 16 from both sides, we get $x^2 = 9$, or $x = 3$.