Answer:
[tex]r=5[/tex]
Step-by-step explanation:
[tex]\text{Solution: }\\\text{Given: C is the center of the circle C and CD}\perp\text{AB.}\\\text{Now,}\\\\\text{1. AD = BD }[\text{The line drawn perpendicular from the center of a circle to }\\\text{}\hspace{2.2cm}\text{a chord bisects the chord.]}\\\\\text{i.e. AD = }\dfrac{1}{2}\times \text{AB}=\dfrac{1}{2}\times8=4[/tex]
[tex]\text{2. Using pythagoras theorem, }\\\text{AC}^2=\text{CD}^2+\text{AD}^2\\\text{or, AC}^2=3^2+4^2=25\\\text{or, AC}=\sqrt{25}\\\therefore\ \text{AC = 5}[/tex]
AC is the radius of the circle, so radius of circle (r) = 5