Answer:
17 units
Step-by-step explanation:
Given 2 congruent chords in the circle, then they are equidistant from the centre and perpendicular
There is a right triangle formed by legs 15 and 8, with radius r being the hypotenuse.
Using Pythagoras' identity in this right angle
r² = 15² + 8² = 225 + 64 = 289 ( take the square root of both sides )
r = = 17