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3 years ago

9

regular octagon rotates 360° about its center. How many times does the image of the octagon coincide with the preimage during th

e rotation?

2 answers:

qwelly [4]3 years ago

8 0

Answer:

8 times

Step-by-step explanation:

An octagon has eight sides of equal length and eight angles of same measure. So, If it is rotated 360 degrees about its center. It would coincide with all of its 8 sides. So, it will coincide with it's pre-image 8 times.

faltersainse [42]3 years ago

4 0

Answer:

Step-by-step explanation:

because A regular octagon is a closed figure with sides of the same length and internal angles of the same size. so if it is rotated 360 degrees it should coincide with its preimage after every 45 degrees.

so 360/45= 8 times

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We take a milk carton from the refrigerator and put it on the table at room temperature. We assume that the temperature of the c

Kisachek [45]

We can solve this problem using separation of variables.

Then apply the initial conditions

EXPLANATION

We were given the first order differential equation

$\frac{dT}{dt}=k(T-a)$

We now separate the time and the temperature variables as follows,

$\frac{dT}{T-a}=kdt$

Integrating both sides of the differential equation, we obtain;

$ln(T-a)=kt +c$

This natural logarithmic equation can be rewritten as;

$T-a=e^{kt +c}$

Applying the laws of exponents, we obtain,

$T-a=e^{kt}\times e^{c}$

$T-a=e^{c}e^{kt}$

We were given the initial conditions,

$T(0)=4$

Let us apply this condition to obtain;

$4-20=e^{c}e^{k(0)}$

$-16=e^{c}$

Now our equation, becomes

$T-a=-16e^{kt}$

or

$T=a-16e^{kt}$

When we substitute a=20,
we obtain,

$T=20-16e^{kt}$

b) We were also given that,

$T(5)=8$

Let us apply this condition again to find k.

$8=20-16e^{5k}$

This implied

$-12=-16e^{5k}$

$\frac{-12}{-16}=e^{5k}$

$\frac{3}{4}=e^{5k}$

We take logarithm to base e of both sides,

$ln(\frac{3}{4})=5k$

This implies that,

$\frac{ln(\frac{3}{4})}{5}=k$

$k=-0.2877$

After 15 minutes, the temperature will be,

$T=20-16e^{-0.2877\times 15}$

$T=20-0.21376$

$T=19.786$

After 15 minutes, the temperature is approximately 20°C

6 0

3 years ago

A circle has a central angle measuring 90° that intersects an arc of length 117.75 inches.

pychu [463]

90 degrees is one quarter of a circle so,
circumference = 4 * 117.75 = 471
circumference = 2 * PI * radius
radius = 471 / (2*PI)
radius = <span> <span> <span> 74.9619781963 </span> </span> </span>

5 0

3 years ago

Read 2 more answers

Carla packed this box with 1 centimeter cubes what is the volume of the box

shusha [124]

Answer: $60\ cm^3$

Step-by-step explanation:

<h3> The complete exercise is attached.</h3>

You can observe in the picture attached that the box is a rectangular prism.

The volume of a rectangular prism can be found with this formula:

$V=lwh$

Where "l" is the length, "w" is the width and "h" is the height.

You know that the lenght of each side of those cubes is 1 centimeter. Therefore, you can multiply the number of cubes on each side of the box by 1 centimeter in order to find the lenght, the width and the height of the box:

$l=(4)(1\ cm)=4\ cm\\\\w=(3)(1\ cm)=3\ cm\\\\h=(5)(1\ cm)=5\ cm$

Now you can substitute the lenght, the width and the height of the box into the formula shown at the beginning of the explanation:

$V=(4\ cm)(3\ cm)(5\ cm)$

Finally, evaluating, you get that the volume of the box is:

$V=60\ cm^3$

4 0

3 years ago

Work out, giving your answer in its simplest form:<br> 2/3 x 3 3/5

kykrilka [37]

Answer: 12/5

Step-by-step explanation:

$3 \frac{3}{5}=\frac{18}{5}\\\\\implies \frac{2}{3} \times 3 \frac{3}{5}=\frac{2}{3} \times \frac{18}{5}\\\\=\frac{36}{15}\\\\=\boxed{\frac{12}{5}}$

5 0

2 years ago

I need help with this problem

Ipatiy [6.2K]

We just check on the graph and see that

the answer is x = -7 and x = 2

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2 years ago

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