Trigonometry : Radians and Conversions

Study concepts, example questions & explanations for Trigonometry

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Example Questions

Example Question #31 : Radians

Convert \(\displaystyle 2^{\circ}\) into radians.

Possible Answers:

\(\displaystyle \frac{\pi}{360}\)

\(\displaystyle \frac{\pi}{180}\)

\(\displaystyle \frac{\pi}{90}\)

\(\displaystyle 2\pi\)

\(\displaystyle \pi\)

Correct answer:

\(\displaystyle \frac{\pi}{90}\)

Explanation:

Recall that there are 360 degrees in a circle which is equivalent to  radians. In order to convert between radians and degrees use the relationship that,

\(\displaystyle 360^\circ=2\pi \Rightarrow 180^\circ=\pi\)

Thus, in order to convert from degrees to radians you need to multiply by \(\displaystyle \frac{\pi}{180}\).

So in this particular case, 

\(\displaystyle 2*\frac{\pi}{180}=\frac{\pi}{90}\).

Example Question #32 : Circles

Convert \(\displaystyle 10^{\circ}\) into radians.

Possible Answers:

\(\displaystyle \frac{\pi}{18}\)

\(\displaystyle \frac{\pi}{180}\)

\(\displaystyle \frac{\pi}{36}\)

\(\displaystyle \frac{10\pi}{9}\)

\(\displaystyle \frac{\pi}{90}\)

Correct answer:

\(\displaystyle \frac{\pi}{18}\)

Explanation:

Recall that there are 360 degrees in a circle which is equivalent to  radians. In order to convert between radians and degrees use the relationship that,

\(\displaystyle 360^\circ=2\pi \Rightarrow 180^\circ=\pi\).

Thus, in order to convert from degrees to radians you need to multiply by \(\displaystyle \frac{\pi}{180}\).

So in this particular case, 

\(\displaystyle 10*\frac{\pi}{180}=\frac{\pi}{18}\).

Example Question #33 : Circles

Convert \(\displaystyle 600^{\circ}\) into radians.

Possible Answers:

\(\displaystyle \frac{11\pi}{5}\)

\(\displaystyle 3\pi\)

\(\displaystyle \frac{\pi}{5}\)

\(\displaystyle \frac{10\pi}{3}\)

\(\displaystyle \frac{10\pi}{9}\)

Correct answer:

\(\displaystyle \frac{10\pi}{3}\)

Explanation:

Recall that there are 360 degrees in a circle which is equivalent to  radians. In order to convert between radians and degrees use the relationship that,

\(\displaystyle 360^\circ=2\pi \Rightarrow 180^\circ=\pi\).

Thus, in order to convert from degrees to radians you need to multiply by \(\displaystyle \frac{\pi}{180}\).

So in this particular case, 

 \(\displaystyle 600*\frac{\pi}{180}=\frac{10\pi}{3}\).

Example Question #32 : Circles

Convert \(\displaystyle \frac{\pi}{2}\) into degrees.

Possible Answers:

\(\displaystyle 55^\circ\)

\(\displaystyle 60^\circ\)

\(\displaystyle 90^\circ\)

\(\displaystyle 180^\circ\)

\(\displaystyle 30^\circ\)

Correct answer:

\(\displaystyle 90^\circ\)

Explanation:

Recall that there are 360 degrees in a circle which is equivalent to \(\displaystyle 2\pi\) radians. In order to convert between radians and degrees use the relationship that,

\(\displaystyle 360^\circ=2\pi \Rightarrow 180^\circ=\pi\)

Therefore, in order to convert from radians to degrees you need to multiply by \(\displaystyle \frac{180}{\pi}\).

So, 

\(\displaystyle \frac{\pi}{2}*\frac{180}{\pi}=90^\circ\).

Example Question #34 : Circles

Convert \(\displaystyle \pi\) into degrees.

Possible Answers:

\(\displaystyle 180^{\circ}\)

\(\displaystyle 90^{\circ}\)

\(\displaystyle 30^{\circ}\)

\(\displaystyle 3.14^{\circ}\)

\(\displaystyle 360^{\circ}\)

Correct answer:

\(\displaystyle 180^{\circ}\)

Explanation:

Recall that there are 360 degrees in a circle which is equivalent to \(\displaystyle 2\pi\) radians. In order to convert between radians and degrees use the relationship that,

\(\displaystyle 360^\circ=2\pi \Rightarrow 180^\circ=\pi\).

Therefore, in order to convert from radians to degrees you need to multiply by \(\displaystyle \frac{180}{\pi}\). So in this particular case, 

\(\displaystyle \pi*\frac{180}{\pi}=180^{\circ}\).

Example Question #35 : Circles

Convert \(\displaystyle 7\pi\) into degrees.

Possible Answers:

\(\displaystyle 1000^{\circ}\)

\(\displaystyle 90^{\circ}\)

\(\displaystyle 1500^{\circ}\)

\(\displaystyle 1260^{\circ}\)

\(\displaystyle 1200^{\circ}\)

Correct answer:

\(\displaystyle 1260^{\circ}\)

Explanation:

Recall that there are 360 degrees in a circle which is equivalent to \(\displaystyle 2\pi\) radians. In order to convert between radians and degrees use the relationship that, \(\displaystyle 360^\circ=2\pi \Rightarrow 180^\circ=\pi\).

Therefore, in order to convert from radians to degrees you need to multiply by \(\displaystyle \frac{180}{\pi}\). So in this particular case, 

 

\(\displaystyle 7\pi*\frac{180}{\pi}=1260^{\circ}\).

Example Question #36 : Circles

Convert \(\displaystyle \frac{4\pi}{3}\) into degrees.

Possible Answers:

\(\displaystyle 100^{\circ}\)

\(\displaystyle 248^{\circ}\)

\(\displaystyle 250^{\circ}\)

\(\displaystyle 200^{\circ}\)

\(\displaystyle 240^{\circ}\)

Correct answer:

\(\displaystyle 240^{\circ}\)

Explanation:

Recall that there are 360 degrees in a circle which is equivalent to \(\displaystyle 2\pi\) radians. In order to convert between radians and degrees use the relationship that, \(\displaystyle 360^\circ=2\pi \Rightarrow 180^\circ=\pi\).

Therefore, in order to convert from radians to degrees you need to multiply by \(\displaystyle \frac{180}{\pi}\). So in this particular case, 

\(\displaystyle \frac{4\pi}{3}*\frac{180}{\pi}=240^{\circ}\).

Example Question #601 : New Sat

Convert \(\displaystyle \frac{9\pi}{5}\) into degrees.

Possible Answers:

\(\displaystyle 324^{\circ}\)

\(\displaystyle 300^{\circ}\)

\(\displaystyle 355^{\circ}\)

\(\displaystyle 333^{\circ}\)

\(\displaystyle 159^{\circ}\)

Correct answer:

\(\displaystyle 324^{\circ}\)

Explanation:

Recall that there are 360 degrees in a circle which is equivalent to \(\displaystyle 2\pi\) radians. In order to convert between radians and degrees use the relationship that, \(\displaystyle 360^\circ=2\pi \Rightarrow 180^\circ=\pi\).

Therefore, in order to convert from radians to degrees you need to multiply by \(\displaystyle \frac{180}{\pi}\).  So in this particular case, 

\(\displaystyle \frac{9\pi}{5}*\frac{180}{\pi}=324^{\circ}\).

Example Question #31 : Radians And Conversions

Convert \(\displaystyle -\frac{\pi}{3}\) into degrees.

Possible Answers:

\(\displaystyle 60^{\circ}\)

\(\displaystyle 180^{\circ}\)

\(\displaystyle -30^{\circ}\)

\(\displaystyle -90^{\circ}\)

\(\displaystyle -60^{\circ}\)

Correct answer:

\(\displaystyle -60^{\circ}\)

Explanation:

Recall that there are 360 degrees in a circle which is equivalent to \(\displaystyle 2\pi\) radians. In order to convert between radians and degrees use the relationship that, \(\displaystyle 360^\circ=2\pi \Rightarrow 180^\circ=\pi\).

Therefore, in order to convert from radians to degrees you need to multiply by \(\displaystyle \frac{180}{\pi}\). So in this particular case, 

\(\displaystyle -\frac{\pi}{3}*\frac{180}{\pi}=-60^{\circ}\).

Example Question #41 : Circles

Convert \(\displaystyle 75^\circ\) into radians

Possible Answers:

\(\displaystyle -\frac {5\pi}{12}\)

\(\displaystyle \frac {5\pi}{18}\)

\(\displaystyle \frac {5\pi}{6}\)

\(\displaystyle \frac {5\pi}{12}\)

Correct answer:

\(\displaystyle \frac {5\pi}{12}\)

Explanation:

Step 1: Recall the formula to change a degree measure into radians:

The formula is: \(\displaystyle Degree\cdot \frac {\pi}{180}\).

Step 2: Plug in the angle:

\(\displaystyle 75 \cdot \frac {\pi}{180}\)

Step 3: Simplify:

We will use the \(\displaystyle 75\) and try to reduce the \(\displaystyle 180\) as much as possible. 

After Dividing by 3:

\(\displaystyle 25 \cdot \frac {\pi}{60}\)

After dividing by 5:

\(\displaystyle 5 \cdot \frac {\pi}{12}=\frac {5\pi}{12}\)


\(\displaystyle 75^\circ\) is \(\displaystyle \frac {5\pi}{12}\) in radians.

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