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olga nikolaevna [1]
4 years ago
11

Simplify this radical. V84 2/21 242 4/21 4/42

Mathematics
2 answers:
dalvyx [7]4 years ago
5 0

Answer:

2√21

Step-by-step explanation:

√81 is √4 times √21

Since √4 is a perfect square, √4 = 2

We are left with 2 times √21

2√21

iragen [17]4 years ago
5 0

Answer:

2√21

Step-by-step explanation:

√84

84 can be written as 4 × 21.

√(4 × 21)

Distribute the square root to both terms.

√4 × √21

4 is a perfect square.

2 × √21

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Reika [66]

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Answer:

  0

Step-by-step explanation:

The forces are equal and opposite, so the net force is zero.

  5N -5N = 0

4 0
3 years ago
An IQ test is designed so that the mean is 100 and the standard deviation is 18 for the population of normal adults. Find the sa
melisa1 [442]

Answer:

At least 98 people need to be sampled. It is not a huge number, that is, it is not difficult to sample 98 people, so it is a reasonable sample size for a real world calculation.

Step-by-step explanation:

We have that to find our \alpha level, that is the subtraction of 1 by the confidence interval divided by 2. So:

\alpha = \frac{1-0.9}{2} = 0.05

Now, we have to find z in the Ztable as such z has a pvalue of 1-\alpha.

So it is z with a pvalue of 1-0.05 = 0.95, so z = 1.645

Now, find the margin of error M as such

M = z*\frac{\sigma}{\sqrt{n}}

In which \sigma is the standard deviation of the population and n is the size of the sample.

In this question:

We need a sample size of at least n.

n is found when M = 3. We have that \sigma = 18.

M = z*\frac{\sigma}{\sqrt{n}}

3 = 1.645*\frac{18}{\sqrt{n}}

3\sqrt{n} = 1.645*18

Simplifying by 3

\sqrt{n} = 1.645*6

(\sqrt{n})^{2} = (1.645*6)^{2}

n = 97.41

Rounding up,

At least 98 people need to be sampled. It is not a huge number, that is, it is not difficult to sample 98 people, so it is a reasonable sample size for a real world calculation.

8 0
3 years ago
If a 12-sided regular polygon rotates about its center, at which angle of rotation will the image of the polygon coincide with t
svp [43]
A full rotation is 360 degrees  so the required angle is 360/12 = 30 degrees.
3 0
3 years ago
Read 2 more answers
Question is below thanks
vichka [17]

Answer:

33.51

Step-by-step explanation:

There's a formula using the value of the angle but I don't remember it so the most easy way is:

A circle has an angle of 360°

so our section has an angle of 60

and we know that 360=60*6

so the area of the circle we divide it by 6 and we get the area we want

A=\pi r^2\\\\A=\pi (8)^2\\\\A=64\pi

divide this by 6

A_1=A/6=64\pi/6\approx 33.51 units squared

5 0
3 years ago
Read 2 more answers
Estimate the value of the irrational number (0.6289731...)2. Up to how many decimal digits is the estimation correct? 4 5 6 7
Salsk061 [2.6K]

Answer:

7 decimal digits

Step-by-step explanation:

Because it ws rounded up to 0.6289731

and the known digits after the decimal are 7 in numbers.

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0.62897..... 5 decimal digits

0.628973.... 6 decimal digits

0.628973 ..... 7 decimal digits

8 0
3 years ago
Read 2 more answers
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