Question #N489
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. 2
B. 3
C. 4
D. 5
Correct Answer is: B
Draw a diagram of the circle with the chord and a radius drawn to an endpoint of the chord. This radius will be perpendicular to the chord and will bisect the chord. This creates a right triangle with the radius as the hypotenuse, half the chord length as one leg, and the distance from the center of the circle to the chord as the other leg. Using the Pythagorean theorem, we have . Solving for the distance, we get , or .