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3 years ago

14

suppose a ladder 20 feet long is placed against a vertical wall 20 feet high. How far would the top of the ladder move down the

wall by pulling out the bottom of the ladder 5 feet?

1 answer:

Taya2010 [7]3 years ago

5 0

You can use the pythagoras theorem.

20^2=5^2+x^2

x^2=400-25
x^2=375

x = 19.36

20-19.36=0.64 feet

The answer is 0.64 feet :)

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True or false: Supporting evidence refers to examples that can be used to help visualize why a statement is true. (1 point) This

matrenka [14]

Answer:

The answer is: This statement is true :)

Step-by-step explanation:

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2 years ago

A number increased by 100% and decreased by 20% is x. what is the number ? NEEDED TODAY

vodka [1.7K]

Answer:

Let's assume the number be 100.

According to the problem , 100 is increased by 100%.

So, new number will be 100+100=200

Now 200 will decreased by 20%.

So, 20% of 200= 0.20*200= 40.

So, again the number has been changed into 200+40=240.

So, x=240

Step-by-step explanation:

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3 years ago

Read 2 more answers

Function p(x), shown below, is translated 10 units up to create function q(x).

natulia [17]

Answer: q(x) = 0.005(x - 40)² + 70

<u>Step-by-step explanation:</u>

f(x) = a(x - h)² + k <em>where a is the vertical stretch and (h, k) is the vertex.</em>

Which coordinate shifts the graph up?<em> The y-coordinate for the vertex is k.</em>

p(x) = 0.005(x - 40)² + 60

q(x) = 0.005(x - 40)² + 60 <u>+ 10</u>

= 0.005(x - 40)² + 70

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3 years ago

A sphere has a radius of 3m. Calculate its surface area and round to the nearest hundredth for your final answer.

bonufazy [111]

Answer:

B

Step-by-step explanation:

formula s =4*pi*r^2

s=4(3.14)(3^2)

s = 12.56(9)s= 113.04

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3 years ago

Which of the following is not one of the 8th roots of unity?

Anika [276]

Answer:

1+i

Step-by-step explanation:

To find the 8th roots of unity, you have to find the trigonometric form of unity.

1. Since $z=1=1+0\cdot i,$ then

$Rez=1,\\ \\Im z=0$

and

$|z|=\sqrt{1^2+0^2}=1,\\ \\\\\cos\varphi =\dfrac{Rez}{|z|}=\dfrac{1}{1}=1,\\ \\\sin\varphi =\dfrac{Imz}{|z|}=\dfrac{0}{1}=0.$

This gives you $\varphi=0.$

Thus,

$z=1\cdot(\cos 0+i\sin 0).$

2. The 8th roots can be calculated using following formula:

$\sqrt[8]{z}=\{\sqrt[8]{|z|} (\cos\dfrac{\varphi+2\pi k}{8}+i\sin \dfrac{\varphi+2\pi k}{8}), k=0,\ 1,\dots,7\}.$

Now

at k=0, $z_0=\sqrt[8]{1} (\cos\dfrac{0+2\pi \cdot 0}{8}+i\sin \dfrac{0+2\pi \cdot 0}{8})=1\cdot (1+0\cdot i)=1;$

at k=1, $z_1=\sqrt[8]{1} (\cos\dfrac{0+2\pi \cdot 1}{8}+i\sin \dfrac{0+2\pi \cdot 1}{8})=1\cdot (\dfrac{\sqrt{2}}{2}+i\dfrac{\sqrt{2}}{2})=\dfrac{\sqrt{2}}{2}+i\dfrac{\sqrt{2}}{2};$

at k=2, $z_2=\sqrt[8]{1} (\cos\dfrac{0+2\pi \cdot 2}{8}+i\sin \dfrac{0+2\pi \cdot 2}{8})=1\cdot (0+1\cdot i)=i;$

at k=3, $z_3=\sqrt[8]{1} (\cos\dfrac{0+2\pi \cdot 3}{8}+i\sin \dfrac{0+2\pi \cdot 3}{8})=1\cdot (-\dfrac{\sqrt{2}}{2}+i\dfrac{\sqrt{2}}{2})=-\dfrac{\sqrt{2}}{2}+i\dfrac{\sqrt{2}}{2};$

at k=4, $z_4=\sqrt[8]{1} (\cos\dfrac{0+2\pi \cdot 4}{8}+i\sin \dfrac{0+2\pi \cdot 4}{8})=1\cdot (-1+0\cdot i)=-1;$

at k=5, $z_5=\sqrt[8]{1} (\cos\dfrac{0+2\pi \cdot 5}{8}+i\sin \dfrac{0+2\pi \cdot 5}{8})=1\cdot (-\dfrac{\sqrt{2}}{2}-i\dfrac{\sqrt{2}}{2})=-\dfrac{\sqrt{2}}{2}-i\dfrac{\sqrt{2}}{2};$

at k=6, $z_6=\sqrt[8]{1} (\cos\dfrac{0+2\pi \cdot 6}{8}+i\sin \dfrac{0+2\pi \cdot 6}{8})=1\cdot (0-1\cdot i)=-i;$

at k=7, $z_7=\sqrt[8]{1} (\cos\dfrac{0+2\pi \cdot 7}{8}+i\sin \dfrac{0+2\pi \cdot 7}{8})=1\cdot (\dfrac{\sqrt{2}}{2}-i\dfrac{\sqrt{2}}{2})=\dfrac{\sqrt{2}}{2}-i\dfrac{\sqrt{2}}{2};$

The 8th roots are

$\{1,\ \dfrac{\sqrt{2}}{2}+i\dfrac{\sqrt{2}}{2},\ i, -\dfrac{\sqrt{2}}{2}+i\dfrac{\sqrt{2}}{2},\ -1, -\dfrac{\sqrt{2}}{2}-i\dfrac{\sqrt{2}}{2},\ -i,\ \dfrac{\sqrt{2}}{2}-i\dfrac{\sqrt{2}}{2}\}.$

Option C is icncorrect.

5 0

2 years ago