The ability to round a number to a number of decimal places or to a number of significant figures means that answers can be written to an agreed degree of accuracy. Watch the video to learn how ...

The circumference of a circle = \(\pi d\) or \(2\pi r\). Look at the sector of the circle shown below. To calculate the length of the arc, we need to know what fraction of the circle is shown. To do ...

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 ...

Now for the important part. Today, as you may know, is Pi Day. Why today? Because it’s March 14—yes, 3/14—and 3.14 is the value of pi to two decimals. Of course, the actual number continues to an ...