Question #N7

A circle has a radius of 5 units. A chord of the circle is 8 units long. What is the distance, in units, from the center of the circle to the chord?
A. 1
B. 3
C. 4
D. 5

Correct Answer is: B

Draw a diagram of the circle with the chord and the radius to the midpoint of the chord. This creates a right triangle where the hypotenuse is the radius, one leg is half the length of the chord, and the other leg is the distance from the center to the chord. Using the Pythagorean Theorem, we have 5² = 4² + d² where d is the distance from the center to the chord. Solving for d gives us d = 3.