A 30-inch chord in a circle is 8 inches from the center of the circle, as shown in the following figure.
Vhat is the length, in inches, of the radius of the circle
See the attached image. Connect the center of the circle to one endpoint of the chord. That forms a right triangle because the radius is drawn perpendicular to the chord -- that's how the distance from center to chord is measured.
The radius splits the chord into two equal parts, each 15 inches long.
The right triangle has legs 8 and 15, so use the Pythagorean Theorem.
