OpenSAT

Draw a diagram of the circle with the chord and a radius drawn to an endpoint of the chord. The radius will be perpendicular to the chord, dividing the chord into two equal segments. The radius, the chord segment, and a radius drawn to the other endpoint of the chord will form a right triangle. The hypotenuse of this triangle will be the radius of the circle, which is 5 units. The other leg of the right triangle will be half of the chord, which is 4 units. The Pythagorean Theorem states that the square of the hypotenuse is equal to the sum of the squares of the legs. Therefore, the square of the distance from the center of the circle to the chord is equal to 5^2 - 4^2 = 25 - 16 = 9. The distance from the center of the circle to the chord is the square root of 9, which is 3.