– 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, ...

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 ...

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 ...