Basic Mathematics
# Length and Area

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

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

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

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