Common Core: High School - Geometry : Similarity, Right Triangles, & Trigonometry

Study concepts, example questions & explanations for Common Core: High School - Geometry

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All Common Core: High School - Geometry Resources

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Example Questions

Example Question #191 : High School: Geometry

To the nearest hundredth, solve  where, , , and .

 

Possible Answers:

Correct answer:

Explanation:

The first step is to create a picture

Plot11

Since we have 2 angles, we can solve for the 3rd angle easily.

Now we can use the Law of Sines to figure out one side

Recall the Law of Sines

Now plug in 16 for B , 78 for A and 47 for a , and solve for the missing side.

Remember to round to the nearest hundredth.

Now we need to solve for the last side of the triangle.

To solve for this, we can use the Law of Cosines.

Lets recall the Law of Cosines.

Example Question #28 : Apply Laws Of Sines And Cosines: Ccss.Math.Content.Hsg Srt.D.11

To the nearest hundredth, solve  where, , , and .

 

Possible Answers:

Correct answer:

Explanation:

The first step is to create a picture

Plot12

Since we have 2 angles, we can solve for the 3rd angle easily.

Now we can use the Law of Sines to figure out one side

Recall the Law of Sines

Now plug in 29 for B , 55 for A and 187 for a , and solve for the missing side.

Remember to round to the nearest hundredth.

Now we need to solve for the last side of the triangle.

To solve for this, we can use the Law of Cosines.

Lets recall the Law of Cosines.

Example Question #93 : Similarity, Right Triangles, & Trigonometry

Using the Law of Cosines, solve for .  Round to the second decimal place.

Screen shot 2020 08 07 at 2.49.50 pm

Possible Answers:

Correct answer:

Explanation:

We will begin by defining the variables in our equation.

 

We will let

 

Next we plug our values into our formulas and solve for .

 

 

Example Question #91 : Similarity, Right Triangles, & Trigonometry

Which of the following expressions properly states the Law of Cosines?  Use the following triangle for reference.

Screen shot 2020 08 13 at 8.30.42 am

Possible Answers:

Correct answer:

Explanation:

The Law of Cosines should look similar to a theorem we use quite commonly for right triangles.  The Law of Cosines is basically the Pythagorean Theorem, but it has an added argument so that it is true for any and all triangles.

Example Question #92 : Similarity, Right Triangles, & Trigonometry

Which of the following expressions properly states the Law of Sines? Use the following triangle for reference.

Screen shot 2020 08 13 at 8.30.42 am

Possible Answers:

Correct answer:

Explanation:

The Law of Sines uses ratios of a triangle’s sides and angles to allow us to be able to solve for unknown sides and/or angles.  This relationship is true for any triangle.

Example Question #96 : Similarity, Right Triangles, & Trigonometry

Use the Law of Cosine to find the missing side.  Round to the second decimal place.

Screen shot 2020 08 20 at 8.44.42 am

Possible Answers:

Correct answer:

Explanation:

We are able to use our equation from the Law of Cosine .  We will start by assigning the values in our figure to the variables in the formula.

 

We will let:

 

Now we can plug these values into our formula.

 

Example Question #97 : Similarity, Right Triangles, & Trigonometry

Using the Law of Sines, solve for  and .  Round to the second decimal place.

Screen shot 2020 08 20 at 10.01.08 am

Possible Answers:

Correct answer:

Explanation:

We begin by labeling our sides and angles according the variables in the equation for the Law of Sines: 

 

We will let

We will begin by solving for .  From our equation , we will leave out the  term to solve for  since it is not needed at this time.

 

 (by cross-multiplication)

 

Now we will solve for .  We could use   for our relationship, but we can also use .

 

 (by cross-multiplication)

 

So 

Example Question #93 : Similarity, Right Triangles, & Trigonometry

Use the Law of Sines to find the missing side lengths and angles.  Round to the second decimal place.

Screen shot 2020 08 20 at 11.17.26 am

Possible Answers:

Correct answer:

Explanation:

We know for the Law of Sines our equation is .  We begin by assigning our values on the figure to variables in the equation.

We will let:

 

 

We will begin by solving for side .

 

 

Using the Law of Sines we need to solve for  and  using the relation .  We do not know either  or .  We are able to solve for  because we know that the angles of a triangle must add up to 180.

 

 

Now we have enough information to solve for  using the Law of Sines

Example Question #1 : Understand That By Similarity, Side Ratios In Right Triangles Are Properties Of The Angles In The Triangle, Leading To Definitions Of Trigonometric Ratios For Acute Angles

Using the sides of a right triangle, what is the definition of ?

Possible Answers:

Correct answer:

Explanation:

We can see this to be true by looking at the following triangle.  

We are considering .  The opposite side to  is  has two adjacent sides, but since  is opposite to the right angle, this is the hypotenuse of the triangle.  So the adjacent side to  must be .  We can set up the following equation to check and make sure that .

 

 

This shows that .

 

 

Example Question #1 : Understand That By Similarity, Side Ratios In Right Triangles Are Properties Of The Angles In The Triangle, Leading To Definitions Of Trigonometric Ratios For Acute Angles

True or False: By similarity, side ratios in right triangles are properties of the angles in the triangle.

 

Possible Answers:

False

True

Correct answer:

True

Explanation:

Similar right triangles are two right triangles that differ in side lengths but have congruent corresponding angles.  This means that if you have an angle, , in the first triangle and an angle, , in the second triangle.  So  .If we are considering the cosine of these two angles.

 

 

Side ratios would also follow from computing the sine and tangent of the angles using their sides as well.  This shows that the side ratios are properties of the angles in the triangles.

 

All Common Core: High School - Geometry Resources

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