– π (pi) is a mathematical constant, approximately equal to 3.14159 If we know the circumference of a circle, we can easily find out its radius by rearranging this formula and solving for ‘r’: r = C / ...

Scientific American presents Math Dude by Quick & Dirty Tips. Scientific American and Quick & Dirty Tips are both Macmillan companies. Throughout history, circles have symbolized many things: unity, ...

STEP 1 - WRAP RIBBON: Take the ribbon and wrap it around a glass. Mark where the ribbon overlaps itself. Image caption, STEP 2 - CUT CIRCUMFERENCE: Cut the ribbon at the point where it overlaps. You ...

Enter the circle’s radius in the indicated field and select the dimension unit. Optionally, you can use the diameter and perimeter – circumference to calculate the circle’s area. If we have a circle ...

The radius of a circle or a sphere is the distance between the center and the edge. The radius can be used to calculate a circle's diameter, area and circumference. Likewise, a sphere's volume is ...