Geometry

Properties of Circles

什么is the area of circle $O$ , if circle $O$ has a radius of 14?

10\pi

196\pi

\pi

14\pi

什么is the radius of circle $O$ , if we know that circle $O$ has an area of $289 \pi$ square units?

什么is the area of a circle with circumference $10\pi$ ?

10\pi

25\pi

5\pi

20\pi

$\Gamma_1$ is a circle with area $27$ . $\Gamma_2$ is a circle whose radius is 3 times the radius of $\Gamma_1$ . What is the area of $\Gamma_2$ ?

什么is the diameter of circle $O$ , if we know that circle $O$ has an area of $36 \pi$ square units?