Trigonometry : Angles

Study concepts, example questions & explanations for Trigonometry

varsity tutors app store varsity tutors android store

Example Questions

Example Question #21 : Complementary And Supplementary Angles

Find the complement of \displaystyle \frac{\pi}{6}.

Possible Answers:

\displaystyle \pi

\displaystyle \frac{\pi }{2}

\displaystyle \frac{\pi }{6}

\displaystyle \frac{\pi }{3}

\displaystyle \frac{\pi }{4}

Correct answer:

\displaystyle \frac{\pi }{3}

Explanation:
Two angles are complementary if their sum is 90°. The same is true even for radian measures which are an equivalent way to write degree measures. To find an angle's complement, subtract it from 90° or \displaystyle \frac{\pi }{2}. Remember, complementary angles are positive.
\displaystyle \frac{\pi}{2}-\frac{\pi }{6}\rightarrow \frac{3\pi }{6}-\frac{\pi }{6}\rightarrow \frac{2\pi }{6}=\frac{\pi }{3}
 
In the middle step we found a common denominator as is custom for subtracting fractions with different denominators.

Example Question #21 : Angles

Find the supplement of 112°.

Possible Answers:

None of the other answers.

\displaystyle 248^{\circ}

\displaystyle 158^{\circ}

\displaystyle 22^{\circ}

\displaystyle 68^{\circ}

Correct answer:

\displaystyle 68^{\circ}

Explanation:

Two angles are supplementary if their sum is 180°. Thus, to find the supplement of an angle, subtract it from 180°. Remember that supplementary angles are positive angles.

\displaystyle 180^{\circ}-112^{\circ}=68^{\circ}

Example Question #22 : Angles

What angle do I add to \displaystyle 50^\circ to make the sum complementary?

Possible Answers:

\displaystyle 50^\circ

\displaystyle 35^\circ

\displaystyle 40^\circ

\displaystyle 45^\circ

Correct answer:

\displaystyle 40^\circ

Explanation:

Step 1: Define complementary angles.

Complementary angles are two angles that must always add up to 90.

Step 2: Find the other angle:

The sum must be 90, so subtract the given angle from the sum to find the missing angle:

\displaystyle 90^\circ-50^\circ=40^\circ

The missing angle is \displaystyle 40^\circ

Example Question #23 : Angles

What must the sum of two angles be, given that the angles are supplementary to each other?

Possible Answers:

\displaystyle 100

\displaystyle 180

\displaystyle 360

\displaystyle 140

Correct answer:

\displaystyle 180

Explanation:

Step 1: Define Supplementary angles. The answer is in the definition:

Two angles, if they are Supplementary to each other, their sum must equal \displaystyle 180 degrees.

The sum of the angles must be \displaystyle 180^\circ

Example Question #21 : Angles

Find the complementary angle of \displaystyle 20^{\circ}

Possible Answers:

\displaystyle 160^{\circ}

\displaystyle -20^{\circ}

\displaystyle 25^{\circ}

\displaystyle 70^{\circ}

\displaystyle 340^{\circ}

Correct answer:

\displaystyle 70^{\circ}

Explanation:

To find the complementary angle of x, you need to subtract x from 90 degrees.

 

\displaystyle Complementary = 90^{\circ} -x

 

So, since we are trying to find the complementary angle of 20 degrees, we have:

 

\displaystyle 90^{\circ}-20^{\circ}=70^{\circ}

Example Question #21 : Complementary And Supplementary Angles

Find the complementary angle of \displaystyle 68.2^{\circ}

Possible Answers:

\displaystyle 111.8^{\circ}

\displaystyle 21.8^{\circ}

\displaystyle 31.8^{\circ}

\displaystyle 391.8^{\circ}

\displaystyle -68.2^{\circ}

Correct answer:

\displaystyle 21.8^{\circ}

Explanation:

To find the complementary angle of x, you need to subtract x from 90 degrees.

 

\displaystyle Complementary = 90^{\circ} -x

 

Since we are trying to find the complementary angle of 68.2 degrees, we have:

 

\displaystyle 90^{\circ}-68.2^{\circ}=21.8^{\circ}

Example Question #24 : Angles

Find the Complementary angle of \displaystyle \frac{\pi}{3} :

Possible Answers:

\displaystyle \frac{2\pi}{3} 

\displaystyle \frac{3\pi}{4} 

\displaystyle \frac{\pi}{4} 

\displaystyle \frac{\pi}{6} 

\displaystyle \frac{\pi}{2} 

Correct answer:

\displaystyle \frac{\pi}{6} 

Explanation:

SInce the given angle is in radians to find the Complementary angle we need to subtract the giving angle from \displaystyle \frac{\pi}{2}. Hence,

 

\displaystyle \frac{\pi}{2}-\frac{\pi}{3}=\frac{\pi}{6}

Example Question #25 : Angles

Find the Complementary angle of \displaystyle \frac{\pi}{7} :

Possible Answers:

\displaystyle \frac{5\pi}{14} 

\displaystyle \frac{3\pi}{7}  

89.55

\displaystyle \frac{\pi}{2}

\displaystyle \frac{6\pi}{7} 

Correct answer:

\displaystyle \frac{5\pi}{14} 

Explanation:

SInce the given angle is in radians to find the Complementary angle we need to subtract the giving angle from \displaystyle \frac{\pi}{2}. Hence,

 

\displaystyle \frac{\pi}{2}-\frac{\pi}{7}=\frac{5\pi}{14}

Example Question #26 : Angles

Find the Supplementary angle of \displaystyle 40^{\circ}

Possible Answers:

\displaystyle -40^{\circ}

\displaystyle 60^{\circ}

\displaystyle 320^{\circ}

\displaystyle 140^{\circ}

\displaystyle 50^{\circ}

Correct answer:

\displaystyle 140^{\circ}

Explanation:

Since we are trying to find the supplementary angle of 40 degrees, we have to:

\displaystyle 180^{\circ}-40^{\circ}=140^{\circ}

Example Question #21 : Complementary And Supplementary Angles

Find the Supplementary angle of \displaystyle 92.67^{\circ}

Possible Answers:

\displaystyle -92.67^{\circ}

\displaystyle 2.67^{\circ}

\displaystyle 87.33^{\circ}

The supplementary angle of \displaystyle 92.67^{\circ} does not exist, because the angle is larger than \displaystyle 90^{\circ}.

\displaystyle 267.33^{\circ}

Correct answer:

\displaystyle 87.33^{\circ}

Explanation:

Since we are trying to find the supplementary angle of 92.67 degrees, we have to:

 

\displaystyle 180^{\circ}-92.67^{\circ}=87.33^{\circ}

Learning Tools by Varsity Tutors