Understanding Radian Measure

A circle O with radius 1 unit has its center placed at the origin. Let A be its intersection with the x-axis at (1,0) and P be another point on its circumference. If we move P along its circumference, then we can determine the distance traveled by P. If we let A be the starting point of P as it moves counterclockwise, then the distance traveled by P is equal to the length of arc AP represented by the red arc in the following figure.

radian 2

To be able to know the length of arc AP, first, we must know the total distance traveled by P from A going counterclockwise and back to A  (i.e. complete revolution). That is, we need to find the circumference of the circle. Since a unit circle has radius 1 unit, its circumference C is  » Read more

Demystifying Degree and Radian Measures


We have learned about angle measures since elementary grades.  In Figure 1, we have a circle with center A, and radius length 1. Angle CAB measures 90 degrees and intercepting minor arc BC.  This is also the same as saying that arc BC is subtending angle CAB. We have also learned  that the entire rotation about the center of a circle is 360 degrees.

Another unit of angle measure besides degree is radian. Now, what is radian? How is it related to degree? » Read more

Mathematics and Multimedia Blog Carnival #3

Welcome the third edition of the Mathematics and Multimedia blog Carnival. This will be the last edition that I will be hosting this year. The fourth edition  will be hosted by Wild About Math!.

Before we begin, let’s have some interesting trivia about the number three. » Read more

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