Question

In the circle above, segment $AB$ is a diameter. If the length of arc $\overline{ADB}$ is $8\pi$ , what is the length of the radius of the circle?

• A. $2$
• B. $4$
• C. $8$
• D. $16$

Answer 1

The correct option is C $8$

Clearly the arc $ADB$ is the half the circumference of the circle.
Which is $\frac{1}{2}\times 2\pi r=8\pi$
$=>r=8$