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3 years ago

How many rotation symmetries does a five-pointed star have? Please show work!!!!!!

Mathematics

2 answers:

yaroslaw [1]3 years ago

6 0

Answer:

4 rotational symmetries for 5 pointed star.

Step-by-step explanation:

To find : How many rotation symmetries does a five-pointed star have?

Solution :

The number of times a shape can be rotated and look the same within one full 360° rotation is called the order of the rotational symmetry, and the angle at which it can be rotated to look the same is called the angle of rotation.

Yes, a 5-point star has rotational symmetry.

A 5-point star is a two-dimensional polygon in the shape of a star with five points, or tips.

The number of rotation is given by,

$n=\frac{360}{5}$

$n=72^\circ$

Therefore, 4 rotational symmetries for 5 pointed star.

VikaD [51]3 years ago

3 0

What do you mean "how many"? Like how many different rotations can you do and it'll be the same or just symmetries in general?

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mart [117]

Answer:

I can only help with a, witch is -3x

Step-by-step explanation:

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3 years ago

A recent survey of students at John Tukey High School revealed that

RoseWind [281]

Answer:

0.5234 = 52.34% probability that at least three of these students are in favor of the proposal to change the dress code.

Step-by-step explanation:

For each student, there are only two possible outcomes. Either they are in favor, or they are not. Students are independent. This means that we use the binomial probability distribution to solve this question.

Binomial probability distribution

The binomial probability is the probability of exactly x successes on n repeated trials, and X can only have two outcomes.

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

In which $C_{n,x}$ is the number of different combinations of x objects from a set of n elements, given by the following formula.

$C_{n,x} = \frac{n!}{x!(n-x)!}$

And p is the probability of X happening.

18% of the students are in favor of changing the dress code.

This means that $p = 0.18$

You randomly select 15 students

This means that $n = 15$

What is the probability that at least three of these students are in favor of the proposal to change the dress code?

This is

$P(X \geq 3) = 1 - P(X < 3)$

In which

$P(X < 3) = P(X = 0) + P(X = 1) + P(X = 2)$

In which

$P(X = x) = C_{n,x}.p^{x}.(1-p)^{n-x}$

$P(X = 0) = C_{15,0}.(0.18)^{0}.(0.82)^{15} = 0.051$

$P(X = 1) = C_{15,1}.(0.18)^{1}.(0.82)^{14} = 0.1678$

$P(X = 2) = C_{15,2}.(0.18)^{2}.(0.82)^{13} = 0.2578$

$P(X < 3) = P(X = 0) + P(X = 1) + P(X = 2) = 0.051 + 0.1678 + 0.2578 = 0.4766$

$P(X \geq 3) = 1 - P(X < 3) = 1 - 0.4766 = 0.5234$

0.5234 = 52.34% probability that at least three of these students are in favor of the proposal to change the dress code.

8 0

3 years ago

What is the x-intercept of the graph y = -4x + 8? A. -4 B. 0 C. 2 D. 8

DaniilM [7]

The correct answer is 2

7 0

4 years ago

Read 2 more answers

Suppose a certain combination lock requires three selections of numbers, each from 1 through 25. (a) How many choices are there

Montano1993 [528]

Answer:

25 choices

Step-by-step explanation:

Given

Possible Combinations: 1 to 25

Selections: 3 numbers

Required

Determine the number of choices of the first number

The first number of the lock can be any of 1 to 25.

This is so because when you counting from 1 to 25, there are 25 numbers

Hence, number of choices is 25 numbers

5 0

3 years ago

The number of accidents that occur at a busy intersection is Poisson distributed with a mean of 4.5 per week. Find the probabili

Mariana [72]

Answer:

a) 0.01111

b) 0.4679

c) 0.33747

Step-by-step explanation:

We are given the following in the question:

The number of accidents per week can be treated as a Poisson distribution.

Mean number of accidents per week = 4.5

$\lambda= 4.5$

Formula:

$P(X =k) = \displaystyle\frac{\lambda^k e^{-\lambda}}{k!}\\\\ \lambda \text{ is the mean of the distribution}$

a) No accidents occur in one week.

$P(x =0)\\\\= \displaystyle\frac{4.5^0 e^{-4.5}}{0!}= 0.01111$

b) 5 or more accidents occur in a week.

$P( x \geq 5) = 1-\displaystyle \sum P(x$

c) One accident occurs today.

The mean number of accidents per day is given by

$\lambda = \dfrac{4.5}{7} = 0.64$

$P(x =1)\\\\= \displaystyle\frac{0.64^1 e^{-0.64}}{1!}= 0.33747$

5 0

3 years ago