Question #N578
A circle has a radius of 5. 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. 6
Correct Answer is: B
Draw a diagram of the circle with the chord and the radius. The distance from the center of the circle to the chord is the perpendicular distance from the center to the chord. This perpendicular line bisects the chord. The two halves of the chord, the radius, and the perpendicular distance form a right triangle with the radius as the hypotenuse. The Pythagorean Theorem tells us that , or . Thus, the distance from the center of the circle to the chord is 3 units.