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Radda [10]
3 years ago
5

(Will give Brainliest/5 Stars if correct answer)

Mathematics
1 answer:
tensa zangetsu [6.8K]3 years ago
7 0
Answer: Choice D) 
The angle between the two vectors is approximately 71.6 degrees

----------------------------------------------
----------------------------------------------

Work Shown: 

Each time I write the word "dot" I mean "dot product". 

|u| = length of vector u
|u| = sqrt(u dot u)
|u| = sqrt(<8,4> dot <8,4>)
|u| = sqrt(8*8 + 4*4)
|u| = sqrt(64 + 16)
|u| = sqrt(80)
|u| = sqrt(16*5)
|u| = sqrt(16)*sqrt(5)
|u| = 4*sqrt(5)

-----------------------

|v| = length of vector v
|v| = sqrt(v dot v)
|v| = sqrt(<9,-9> dot <9,-9>)
|v| = sqrt(9*9 + (-9)*(-9))
|v| = sqrt(81+81)
|v| = sqrt(2*81)
|v| = sqrt(2)*sqrt(81)
|v| = sqrt(2)*9
|v| = 9*sqrt(2)

-----------------------

u dot v = <8,4> dot <9,-9>
u dot v = 8*9 + 4*(-9)
u dot v = 72-36
u dot v = 36

-----------------------

cos(theta) = (u dot v)/(|u|*|v|)
cos(theta) = (36)/(4*sqrt(5)*9*sqrt(2))
cos(theta) = (36)/(36*sqrt(10))
cos(theta) = 1/(sqrt(10))
cos(theta) = sqrt(10)/10
theta = arccos(sqrt(10)/10)
theta = 71.56505
which rounds to 71.6 when rounding to one decimal place (nearest tenth)

That's why the approximate answer is roughly 71.6 degrees

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3 years ago
Read 2 more answers
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However, this includes the base of the cone and the hats do NOT have
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So the formula becomes pi * radius * sqrt( height^2 + radius^2)

diameter = 16
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The surface area of ONE of the hats is pi * 8 * sqrt( 9^2 + 8^2)
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Consider the enlargement of the pentagon. A small pentagon has a bottom side length of x centimeters and left side length of 7 c
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When the pentagon is drawn to scale then its value of x will be x=3.3 cm

<h3>What is the pentagon?</h3>

The pentagon is defined as the shape having five sides connected together.

Now it is given in the question that

For small pentagone

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left =7 cm

For larger pentagone

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Now since the pentagon is actually dilated from its size to the new bigger size. It means that the equivalent ratio of both the pentagons will be equal.

For smaller pentagon

\rm Equivalent \ Ratio = \dfrac{Bottom}{Left} =\dfrac{x}{7}

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Since both, the ratio is the same

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