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4 years ago

Through which angle of rotation does the image of a regular pentagon coincide with its preimage?

1 answer:

4 0

Answer: 72° or any muliple of it: 72°, 144°, 216°, 288°, 360°, ...

It can be either clockwise or counterclockwise.

Explanation:

Thi is because a regular pentagon has 5 congruent sides.

Then you determine the angle of rotation by dividing 360° (a complete turn) by the number of sides (5)

360° / 5 = 72°.

Then every 72° the segments of the image will overlap those of the preimage.

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Standard deviation of 300, 785, 670, 187, 760, 724

White raven [17]

STEP 1

Mean = $\frac{300+785+670+187+760+724}{6} = \frac{3426}{6}=571$

STEP 2

Subtract the mean from each data value then square the answer
$300-571=-271$ ⇒ $(-271)^{2} =73441$
$785-571=214$ ⇒ $(214)^{2}=45796$
$670-571=99$ ⇒ $(99)^{2}=9801$
$187-571=-384$ ⇒ $(-384)^{2} =147456$
$760-571=189$ ⇒ $189^{2}=35721$
$724-571=153$ ⇒ $153^{2} =23409$

STEP 3

Add the squared answers in STEP 2 then find the mean

$\frac{73441+45796+9801+147456+35721+23409}{6}= \frac{335624}{6}=55937.3$

STEP 4

Square root the answer in STEP 3
$\sqrt{55937.3} =236.5$

Standard deviation is 236.5

7 0

3 years ago

Which equation describes a parabola that opens up or down and whose vertex is at the point (h,v)

Serggg [28]

y = a ( x - h)^2 + v

a is positive when the parabola opens up and negative when it opens down.

7 0

4 years ago

AC. DF, and GI are parallel. Use the figure to complete the proportion.<br> AD/DG = ?/EH

ivanzaharov [21]

Answer:

BE.

Step-by-step explanation:

If AD is to DG, then BE must be to EH, and CF must be to FI.

3 0

3 years ago

Read 2 more answers

Find the missing value so that the line passing through the points has the given slope.

Dominik [7]

Answer:

y = 2

Step-by-step explanation:

use slope formula:

(4 - y) / (3 - 10) = -2/7

4-y / -7 = -2 /7

cross-multiply:

7(4 - y) = (-7)(-2)

28 - 7y = 14

-7y = -14

y = 2

4 0

3 years ago

Bill ate 1/4 pound of trail mix on his first break during a hiking trip. On his second break, he ate 1/6 pound. How many pounds

Arada [10]

1/4 + 1/6 = (6+4)/24 = 10/24 = 5/12

3 0

4 years ago

Read 2 more answers