High School Math : Understanding Radians and Conversions

Study concepts, example questions & explanations for High School Math

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Example Questions

Example Question #41 : The Unit Circle And Radians

If angle \displaystyle B equals \displaystyle 136^{\circ}, what is the equivalent angle in radians (to the nearest hundredth)?

Possible Answers:

\displaystyle 1.18\ rad

\displaystyle 2.37\ rad

\displaystyle 7.79\ rad

\displaystyle 136\ rad

\displaystyle 23.7\ rad

Correct answer:

\displaystyle 2.37\ rad

Explanation:

To convert between radians and degrees, it is important to remember that: 

\displaystyle \pi\, rad = 180^{\circ}

With this relationship in mind, we can convert from degrees to radians with the following formula:

\displaystyle 136^{\circ}\cdot \frac{\pi}{180^{\circ}} = 2.37\,rad
 

Example Question #62 : Trigonometry

If \displaystyle \angle A equals \displaystyle 45^{\circ}, what is the equivalent angle in radians (to the nearest hundredth)? 

Possible Answers:

\displaystyle 0.56\ rad

\displaystyle 0.79\ rad

\displaystyle 3.14\ rad

\displaystyle 4.71\ rad

\displaystyle 1.57\ rad

Correct answer:

\displaystyle 0.79\ rad

Explanation:

To convert between radians and degrees, it is important to remember that: 

\displaystyle \pi\, rad = 180^{\circ}

With this relationship in mind, we can convert from degrees to radians with the following formula:

\displaystyle 45^{\circ}\cdot \frac{\pi}{180^{\circ}} = 0.79\,rad

Example Question #63 : Trigonometry

If\displaystyle \angle B is \displaystyle 275^{\circ}, what is the equivalent angle in radians (to the nearest hundredth)? 

Possible Answers:

\displaystyle 3.27\ rad

\displaystyle 2.40\ rad

\displaystyle 4.80\ rad

\displaystyle 9.60\ rad

\displaystyle 1.37\ rad

Correct answer:

\displaystyle 4.80\ rad

Explanation:

To convert between radians and degrees, it is important to remember that:

\displaystyle \pi\, rad = 180^{\circ}

With this relationship in mind, we can convert from degrees to radians with the following formula:

\displaystyle 275^{\circ}\cdot \frac{\pi}{180^{\circ}} = 4.80\,rad
 

Example Question #62 : Trigonometry

If an angle is \displaystyle 98^{\circ}, what is the equivalent angle in radians (to the nearest hundredth)? 

Possible Answers:

\displaystyle 0.86\ rad

\displaystyle 1.27\ rad

\displaystyle 3.14\ rad

\displaystyle 1.71\ rad

\displaystyle 3.42\ rad

Correct answer:

\displaystyle 1.71\ rad

Explanation:

To convert between radians and degrees, it is important to remember that: 

\displaystyle \pi\, rad = 180^{\circ}

With this relationship in mind, we can convert from degrees to radians with the following formula:

\displaystyle 98^{\circ}\cdot \frac{\pi}{180^{\circ}}= 1.71\,rad

Example Question #65 : Trigonometry

What angle below is equivalent to \displaystyle 90^{\circ}?

Possible Answers:

\displaystyle 4\pi\,radians

\displaystyle \frac{\pi}{4}\,radians

\displaystyle \pi\,radians

\displaystyle \frac{\pi}{2}\,radians

\displaystyle 2\pi\,radians

Correct answer:

\displaystyle \frac{\pi}{2}\,radians

Explanation:

To convert between radians and degrees, it is important to remember that: 

\displaystyle \pi\, radians = 180\, degrees

With this relationship in mind, we can convert from degrees to radians with the following formula:

\displaystyle 90^{\circ}\cdot \frac{\pi}{180^{\circ}} = \frac{1}{2}\cdot \pi = \frac{\pi}{2}\,radians
 

Example Question #71 : Trigonometry

If an angle is 2.43 radians, what is the equivalent angle in degrees? 

Possible Answers:

\displaystyle 139.23^{\circ}

\displaystyle 127^{\circ}

\displaystyle 45^{\circ}

\displaystyle 90^{\circ}

\displaystyle 145^{\circ}

Correct answer:

\displaystyle 139.23^{\circ}

Explanation:

To answer this question, it is important to remember the relationship:

\displaystyle \pi\,radians = 180\,degrees

From here, we can set up the following formula: 

\displaystyle 2.43\,rad\cdot \frac{180^\circ}{\pi\,rad} = 139.23^{\circ}

Multiplying across, we see that the units of radians cancel out and we are left with units in degrees. 

Example Question #71 : Trigonometry

If an angle equals 5.75 radians, what is the equivalent angle in degrees? 

Possible Answers:

\displaystyle 360^{\circ}

\displaystyle 90^{\circ}

\displaystyle 329.45^{\circ}

\displaystyle 3.14^{\circ}

\displaystyle 180^{\circ}

Correct answer:

\displaystyle 329.45^{\circ}

Explanation:

To answer this question, it is important to remember the relationship:

\displaystyle \pi\,radians = 180\,degrees

From here, we can set up the following formula: 

\displaystyle 5.75\,rad\cdot \frac{180^\circ}{\pi\,rad} = 329.45^{\circ}

Multiplying across, we see that the units of radians cancel out and we are left with units in degrees. 

Example Question #33 : Understanding Radians And Conversions

If an angle equals 15.71 radians, what is the equivalent angle in degrees?

Possible Answers:

\displaystyle 3.14^{\circ}

\displaystyle 670^{\circ}

\displaystyle 900^{\circ}

\displaystyle 45^{\circ}

\displaystyle 1.57^{\circ}

Correct answer:

\displaystyle 900^{\circ}

Explanation:

To answer this question, it is important to remember the relationship:

\displaystyle \pi\,radians = 180\,degrees

From here, we can set up the following formula: 

\displaystyle 15.71\,rad\cdot \frac{180^\circ}{\pi\,rads} = 900^{\circ}

Multiplying across, we see that the units of radians cancel out and we are left with units in degrees. 

Example Question #43 : The Unit Circle And Radians

If an angle equals 6.4 radians, what is the equivalent angle in degrees? 

Possible Answers:

\displaystyle 360^{\circ}

\displaystyle 180^{\circ}

\displaystyle 366.69^{\circ}

\displaystyle 31.4^{\circ}

\displaystyle 5.78^{\circ}

Correct answer:

\displaystyle 366.69^{\circ}

Explanation:

To answer this question, it is important to remember the relationship:

\displaystyle \pi\,radians = 180\,degrees

From here, we can set up the following formula: 

\displaystyle 6.4\,rad\cdot \frac{180^\circ}{\pi\,rads}= 366.69^{\circ}

Multiplying across, we see that the units of radians cancel out and we are left with units in degrees. 

Example Question #44 : The Unit Circle And Radians

If an angle is 3.55 radians, what is the equivalent angle in degrees? 

Possible Answers:

\displaystyle 203.40^{\circ}

\displaystyle 270.45^{\circ}

\displaystyle 360^{\circ}

\displaystyle 200^{\circ}

\displaystyle 146.87^{\circ}

Correct answer:

\displaystyle 203.40^{\circ}

Explanation:

To answer this question, it is important to remember the relationship:

\displaystyle \pi\,radians = 180\,degrees

From here, we can set up the following formula: 

\displaystyle 3.55\,rad\cdot \frac{180^\circ}{\pi\,rad} = 203.40^{\circ}

Multiplying across, we see that the units of radians cancel out and we are left with units in degrees. 

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