High School Math : Trigonometry

Study concepts, example questions & explanations for High School Math

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Example Questions

Example Question #1791 : High School Math

Convert \(\displaystyle \frac{8\pi }{3}\) to degrees. 

Possible Answers:

\(\displaystyle 160^{\circ}\)

\(\displaystyle 480^{\circ}\)

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

\(\displaystyle 380^{\circ}\)

\(\displaystyle 560^{\circ}\)

Correct answer:

\(\displaystyle 480^{\circ}\)

Explanation:

Multiply by \(\displaystyle \frac{180}{\pi }\) and then simplify. The answer is \(\displaystyle 480^{\circ}\)

Example Question #26 : Understanding Radians And Conversions

How many radians are in \(\displaystyle 230^\circ\)?

Possible Answers:

\(\displaystyle 8.03\: rad\)

\(\displaystyle 2.56\: rad\)

\(\displaystyle 6.44\: rad\)

\(\displaystyle 0.81\: rad\)

\(\displaystyle 2.46\: rad\)

Correct answer:

\(\displaystyle 8.03\: rad\)

Explanation:

The ratio of degrees to radians is \(\displaystyle \frac{180^\circ}{2\pi \,radians}\). Set up a proportion and solve.

\(\displaystyle \frac{230^\circ}{x}=\frac{180^\circ}{2\pi \, rad}\)

\(\displaystyle 230^\circ*2\pi \ rad=180^\circ*x\)

\(\displaystyle \frac{230^\circ*2\pi \ rad}{180^\circ}=x\)

\(\displaystyle 2.56\pi \ rad=x\)

\(\displaystyle 8.03\ rad=x\)

Example Question #27 : Understanding Radians And Conversions

How many degrees are in \(\displaystyle \frac{5}{3}\pi\) radians?

Possible Answers:

\(\displaystyle 150^\circ\)

\(\displaystyle 54^\circ\)

\(\displaystyle 216^\circ\)

\(\displaystyle 300^\circ\)

\(\displaystyle 108^\circ\)

Correct answer:

\(\displaystyle 300^\circ\)

Explanation:

The conversion between radians and degrees is \(\displaystyle \pi={180^\circ}\). We can use this as a ratio to solve:

\(\displaystyle \frac{\frac{5}{3}\pi}{x^\circ}=\frac{\pi}{180^\circ}\)

Cross multipy.

\(\displaystyle x^\circ*\pi=\frac{5}{3}\pi *180^\circ\)

Notice that the \(\displaystyle \pi\)'s cancel out.

\(\displaystyle x^\circ=\frac{5}{3} *180^\circ\)

\(\displaystyle x^\circ=300^\circ\)

Example Question #61 : Trigonometry

How many degrees are in \(\displaystyle \frac{2}{3}\pi\) radians?

Possible Answers:

\(\displaystyle 270^\circ\)

\(\displaystyle 60^\circ\)

\(\displaystyle 120^\circ\)

\(\displaystyle 180^\circ\)

\(\displaystyle 240^\circ\)

Correct answer:

\(\displaystyle 120^\circ\)

Explanation:

The conversion between radians and degrees is \(\displaystyle \pi={180^\circ}\). We can then create a ratio to solve:

\(\displaystyle \frac{\frac{2}{3}\pi}{x^\circ}=\frac{\pi}{180^\circ}\)

Cross multipy:

\(\displaystyle x^\circ*\pi=\frac{2}{3}\pi *180^\circ\)

Notice that the \(\displaystyle \pi\)'s cancel out.

\(\displaystyle x^\circ=\frac{2}{3} *180^\circ\)

\(\displaystyle x^\circ=120^\circ\)

Example Question #34 : The Unit Circle And Radians

If Angle \(\displaystyle A\) equals \(\displaystyle 72^{\circ}\), what is the equivalent angle in radians (to the nearest hundredth)? 

Possible Answers:

\(\displaystyle 1256.6\ radians\)

\(\displaystyle 0.628\ radians\)

\(\displaystyle 1.26\ radians\)

\(\displaystyle 4.125\ radians\)

\(\displaystyle 4125.29\ radians\)

Correct answer:

\(\displaystyle 1.26\ radians\)

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:

\(\displaystyle 72^{\circ}\cdot \frac{\pi}{180^{\circ}} = 1.26\,rad\)
 

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 #1792 : High School Math

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

Possible Answers:

\(\displaystyle 2.40\ rad\)

\(\displaystyle 9.60\ rad\)

\(\displaystyle 4.80\ rad\)

\(\displaystyle 3.27\ rad\)

\(\displaystyle 1.37\ rad\)

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:

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

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