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3 years ago

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A city plans to build a new rectangular-shaped park. The perimeter of the park will be 940 meters. The width of the park will be

300 meters. What will be the length, in meters, of the new park?

1 answer:

xz_007 [3.2K]3 years ago

3 0

Answer: 170 meters.

Step-by-step explanation:

1. The formula for calculate the perimeter of a rectangle is:

$P=2l+2w$

Where $l$ is the lenght and $w$ is the width.

2. You must solve for the lenght.

3. The problem gives the perimeter and the width, then, when you substitute these values you obtain the following result:

$2l=P-2w\\l=\frac{P-2w}{2}\\l=\frac{940m-2(300m)}{2}\\l=170m$

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Determine which of the lines are parallel and which of the lines are perpendicular. Select all of the statements that are true.

grandymaker [24]

Answer:

Lines a and b are parallel

Lines a and c are perpendicular

Lines d and c are perpendicular

Step-by-step explanation:

we know that

The formula to calculate the slope between two points is equal to

$m=\frac{y2-y1}{x2-x1}$

Part 1) Find the slope of Line a

we have the points

(-3,4) and (3,6)

substitute in the formula

$m=\frac{6-4}{3+3}$

$m=\frac{2}{6}$

simplify

$m_a=\frac{1}{3}$

Part 2) Find the slope of Line b

we have the points

(-10,-3) and (-8,3)

substitute in the formula

$m=\frac{3+3}{-8+10}$

$m=\frac{6}{2}$

$m_b=3$

Part 3) Find the slope of Line c

we have the points

(0,5) and (3,-4)

substitute in the formula

$m=\frac{-4-5}{3-0}$

$m=\frac{-9}{3}$

$m_c=-3$

Part 4) Find the slope of Line d

we have the points

(4,-7) and (13,-4)

substitute in the formula

$m=\frac{-4+7}{13-4}$

$m=\frac{3}{9}$

simplify

$m_d=\frac{1}{3}$

Part 5) Compare the slopes

Remember that

If two lines are parallel then their slopes are the same

If two lines are perpendicular then their slopes are opposite reciprocal

we have

$m_a=\frac{1}{3}$

$m_b=3$

$m_c=-3$

$m_d=\frac{1}{3}$

therefore

Lines a and b are parallel (slopes are equal)

Lines a and c are perpendicular (slopes are opposite reciprocal)

Lines d and c are perpendicular (slopes are opposite reciprocal)

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3 years ago

A machinist can produce 12 parts in 40 min.how many parts can the machinist produce in 4 hours?

expeople1 [14]

Answer:

72 parts

Steps:

Convert the 4 hours into minutes. There are 60 minutes in an hour. Therefore, 4 hours = 240 minutes.

Divide 240 minutes by 40 minutes. This equals 6. Therefore, the machinist can produce the 12 parts 6 times in 4 hours.

Finally, multiply the 12 parts by the 6 times he can produce. Therefore, the machinist can produce 72 parts in 4 hours.

7 0

3 years ago

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Let the following sample of 8 observations be drawn from a normal population with unknown mean and standard deviation:

Vikentia [17]

Answer:

a

$\= x = 18.5$ , $\sigma = 5.15$

b

$15.505 < \mu < 21.495$

c

$14.93 < \mu < 22.069$

Step-by-step explanation:

From the question we are are told that

The sample data is 21, 14, 13, 24, 17, 22, 25, 12

The sample size is n = 8

Generally the ample mean is evaluated as

$\= x = \frac{\sum x }{n}$

$\= x = \frac{ 21 + 14 + 13 + 24 + 17 + 22+ 25 + 12 }{8}$

$\= x = 18.5$

Generally the standard deviation is mathematically evaluated as

$\sigma = \sqrt{\frac{\sum (x- \=x )^2}{n}}$

$\sigma = \sqrt{\frac{\sum ((21 - 18.5)^2 + (14-18.5)^2+ (13-18.5)^2+ (24-18.5)^2+ (17-18.5)^2+ (22-18.5)^2+ (25-18.5)^2+ (12 -18.5)^2 )}{8}}$

$\sigma = 5.15$

considering part b

Given that the confidence level is 90% then the significance level is evaluated as

$\alpha = 100-90$

$\alpha = 10\%$

$\alpha = 0.10$

Next we obtain the critical value of $\frac{ \alpha }{2}$ from the normal distribution table the value is

$Z_{\frac{ \alpha }{2} } = 1.645$

The margin of error is mathematically represented as

$E = Z_{\frac{ \alpha }{2} } * \frac{\sigma }{\sqrt{n} }$

=> $E =1.645 * \frac{5.15 }{\sqrt{8} }$

=> $E = 2.995$

The 90% confidence interval is evaluated as

$\= x - E < \mu < \= x + E$

substituting values

$18.5 - 2.995 < \mu < 18.5 + 2.995$

$15.505 < \mu < 21.495$

considering part c

Given that the confidence level is 95% then the significance level is evaluated as

$\alpha = 100-95$

$\alpha = 5\%$

$\alpha = 0.05$

Next we obtain the critical value of $\frac{ \alpha }{2}$ from the normal distribution table the value is

$Z_{\frac{ \alpha }{2} } = 1.96$

The margin of error is mathematically represented as

$E = Z_{\frac{ \alpha }{2} } * \frac{\sigma }{\sqrt{n} }$

=> $E =1.96 * \frac{5.15 }{\sqrt{8} }$

=> $E = 3.569$

The 95% confidence interval is evaluated as

$\= x - E < \mu < \= x + E$

substituting values

$18.5 - 3.569 < \mu < 18.5 + 3.569$

$14.93 < \mu < 22.069$

8 0

3 years ago

Please help me with this very hard question. Determine if each pair of expressions is equivalent. Mark all equivalent expression

Shalnov [3]

It’s the 3rd one hopefully that helps you

7 0

2 years ago

What’s the answer ?

Sliva [168]

Answer:

C) an obtuse triangle

Step-by-step explanation:

Since the main angle (the angle that corresponds to the longest side) is considered to measure more than 90°, it is an obtuse triangle.

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3 years ago

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