McGraw Hill Glencoe Algebra 2, 2012
MH
McGraw Hill Glencoe Algebra 2, 2012 View details
2. Angles and Angle Measure
Continue to next subchapter

Exercise 53 Page 804

Express the one complete rotation of a circle in terms of degrees and radians.

See solution.

Practice makes perfect

We are asked to describe what one degree and one radian represent. We know that one complete rotation of a circle equals 360 ^(∘).

Degrees in a circle

Therefore, one degree represents an angle measure that equals 1360 of a rotation around a circle. On the other hand, one radian is defined as the measure of an angle in standard position that intercepts an arc of length r.

Let's now recall that the circumference of a circle is 2 π r. Therefore, one complete rotation of a circle is also equal to 2 π radians. This means that 360 ^(∘) and 2 π radians represent the same measure. 360 ^(∘) = 2 π ⟺ 180 ^(∘)= π By using this equation, we can create our conversion factors to convert degrees to radians or radians to degrees. Degrees to Radians: π/180 ^(∘) Radians to Degrees: 180 ^(∘)/π To convert degrees to radians we can multiply the number of degrees by π 180 ^(∘), and to convert radians to degrees we can multiply the number of radians by 180 ^(∘) π. Note that each of these ratios has a value of 1 since the numerator and denominator of each are equal.