help please I would appreciate it thank u

Answer:
radius = 7.5 cm
Step-by-step explanation:
Since M is the midpoint of the chord AB then OM is perpendicular to AB
Using Pythagoras' identity in right triangle OMB with hypotenuse OB, the radius of the circle, then
OB² = OM² + MB² = 4.5² + 6² = 20.25 + 36 = 56.25 ( take square root of both sides )
OB = radius = [tex]\sqrt{56.25}[/tex] = 7.5