An indoor track is made up of a rectangular region with two semi-circles at the ends. The distance around the track is 400 meters. What dimensions for the rectangular region maximize the area of the rectangular region?

Answers

Answer 1

Answer:

width of rectangle = 2R = (200/π) = 400/π meters

length of rectangle = 400 - π(200/π) = 400 - 200 = 200 meters

Step-by-step explanation:

The distance around the track (400 m) has two parts:  one is the circumference of the circle and the other is twice the length of the rectangle.

Let L represent the length of the rectangle, and R the radius of one of the circular ends.  Then the length of the track (the distance around it) is:

Total = circumference of the circle + twice the length of the rectangle, or

         =                    2πR                    + 2L    = 400 (meters)  

This equation is a 'constraint.'  It simplifies to πR + L = 400.  This equation can be solved for R if we wish to find L first, or for L if we wish to find R first.  Solving for L, we get L = 400 - πR.

We wish to maximize the area of the rectangular region.  That area is represented by A = L·W, which is equivalent here to A = L·2R = 2RL.  We are to maximize this area by finding the correct R and L values.

We have already solved the constraint equation for L:  L = 400 - πR.  We can substitute this 400 - πR for L in

the area formula given above:    A = L·2R = 2RL = 2R)(400 - πR).  This product has the form of a quadratic:  A = 800R - 2πR².  Because the coefficient of R² is negative, the graph of this parabola opens down.  We need to find the vertex of this parabola to obtain the value of R that maximizes the area of the rectangle:        

                                                                   -b ± √(b² - 4ac)

Using the quadratic formula, we get R = ------------------------

                                                                            2a

                                                   -800 ± √(6400 - 4(0))           -1600

or, in this particular case, R = ------------------------------------- = ---------------

                                                        2(-2π)

            -800

or R = ----------- = 200/π

            -4π

and so L = 400 - πR (see work done above)

These are the dimensions that result in max area of the rectangle:

width of rectangle = 2R = (200/π) = 400/π meters

length of rectangle = 400 - π(200/π) = 400 - 200 = 200 meters


Related Questions

An interior designer hangs canvas paintings along a hallway. If the interior designer uses canvas paintings with length measuring
9
inches and places them side by side along the hallway that has a length of
24
feet, how many paintings does the designer hang?

Answers

The number of paintings the designer can hang is 32.

In order to determine how many paintings the painter can hang, the length of the hallway would be divided by the length of the paintings.

Number of paintings = length of hallway / length of paintings

The unit of measurement of the hallway and the paintings have to be the same length,

1 foot = 12 inches

24 feet x 12 = 288 inches

Number of paintings = 288 / 9 = 32 paintings

To learn more about division, please check: https://brainly.com/question/194007

2x - 5y = 6 and -2x + 7y = 14

*Using elimination*​

Answers

2x-5y+ (-2x) + 7y= 6+14
2y = 20
y= 10
2x-5(10)=6
2x= 56
x= 28
here is the ans.hope this helps!

does the graph represent a function?

Answers

Answer:

No

Step-by-step explanation:

fails the vertical line test, a test to see if a vertical line can touch 2 points on a graph at the same time.

A breakfast cereal producer makes its most popular product by combining just raisins and flakes in each box of cereal. The amounts of flakes in the boxes of this cereal are normally distributed with a mean of 370\,\text{g}370g370, start text, g, end text and a standard deviation of 24\,\text{g}24g24, start text, g, end text. The amounts of raisins are also normally distributed with a mean of 170\,\text{g}170g170, start text, g, end text and a standard deviation of 7\,\text{g}7g7, start text, g, end text.
Let T=T=T, equals the total amount of product in a randomly selected box, and assume that the amounts of flakes and raisins are independent of each other.
Find the probability that the total amount of product is less than 575\,\text{g}575g575, start text, g, end text.
You may round your answer to two decimal places.
P(T<575)\approx

Answers

Using the normal distribution, it is found that there is a 0.9192 = 91.92% probability that the total amount of product is less than 575 g.

In a normal distribution with mean [tex]\mu[/tex] and standard deviation [tex]\sigma[/tex], the z-score of a measure X is given by:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

It measures how many standard deviations the measure is from the mean.  After finding the z-score, we look at the z-score table and find the p-value associated with this z-score, which is the percentile of X.When two normal variables are added, the mean is the sum of the means while the standard deviation is the square root of the sum of the variances.

In this problem, the product is composed by flakes and raisins, and we have that:

[tex]\mu_F = 370, \sigma_F = 24, \mu_R = 170, \sigma_R = 7[/tex]

Hence, the distribution for the total amount of product has mean and standard deviation given by:

[tex]\mu = \mu_F + \mu_R = 370 + 170 = 540[/tex]

[tex]\sigma = \sqrt{\sigma_F^2 + \sigma_R^2} = \sqrt{24^2 + 7^2} = 25[/tex]

The probability that the total amount of product is less than 575 g is the p-value of Z when X = 575, hence:

[tex]Z = \frac{X - \mu}{\sigma}[/tex]

[tex]Z = \frac{575 - 540}{25}[/tex]

[tex]Z = 1.4[/tex]

[tex]Z = 1.4[/tex] has a p-value of 0.9192.

0.9192 = 91.92% probability that the total amount of product is less than 575 g.

A similar problem is given at https://brainly.com/question/22934264

8y + 15x + 3y - 12x - 3x

Answers

Answer:

11y is the exact value.

Step-by-step explanation:

The original price of a dress is 95.00. A discount of 10% is offered for cash payment. How much does one save by paying cash for the dress?

Answers

Answer:

10% of 95 is 9.5

So 95 - 9.5 = 85.5

Match the event with the most appropriate probability word: The roll of a normal fair dice will show a 7.

A. Certainly
B. Likely
C. Evens
D. Unlikely
E. Impossible
F. Other

Answer this, plz.

Answers

Answer:

Option 3

Evens

. . . . . .. . ..

solve the following stystem -4x + 2y = 0 and x + y = -1

Answers

The (x, y) values are (-1/3, -2/3) respectively

geomtry plz help 15 points

Answers

Answer:

it should be 60°. the single marks on each side means they are all equal

Answer:

m∠L=60º

Step-by-step explanation:

The triangle is an equilateral triangle meaning that all angles and sides are equal.

m∠L=60º

Hope this helps :)

which number will reach if we move 6 steps to the right -3

Answers

Answer:

If you meant -3 + 6, then the correct answer is 3.

You should put some extra effort in composing questions with all the required information, like a picture maybe.

Answer:

your answer has to be 3

Step-by-step explanation:

if you were to move to the right in number line you have to add so -3+6 is equals to 3

What is 75.65 rounded to the nearest whole number?​

Answers

It is 76 as the other person said, what I like to think to help me remember is five or more raise the score, 4 or less, let it rest

A stone is launched into the air from a height of 240 feet. The height, h, of the stone, in feet, t seconds after launch is given by
the formula h = 16t^2 + 32t+ + 240. After how long will the stone hit the ground?

Answers

A projectile is an object launched into space, and moving under the influence of gravity and momentum. The stone here is an example. Thus, the time taken for the stone to reach the ground is 10 seconds.

On launching of the stone into space, it behaves as a projectile. Thus moving under the influence of gravity and its momentum. Its momentum is the product of its mass and velocity.

The height h, is given as:

h = 16[tex]t^{2}[/tex] + 32t + 240

Differentiating the expression with respect to t, we have;

32t + 32 = 0

t = -1 seconds

Substitute the value of time, t, in the equation for the height;

h = 16 - 32 + 240

  = 224

h = 224 m

Total height, S = 240 + 224

                         = 464

S = 464 m

The total height covered by the stone is 464 m.

From the second equation of free fall,

S = Ut + [tex]\frac{1}{2}[/tex]g[tex]t^{2}[/tex]

S = [tex]\frac{1}{2}[/tex]g[tex]t^{2}[/tex]

464 = [tex]\frac{1}{2}[/tex]*9.8*[tex]t^{2}[/tex]

[tex]t^{2}[/tex] = [tex]\frac{928}{9.8}[/tex]

  = 94.694

t = [tex]\sqrt{94.694}[/tex]

 = 9.7311

t 10 seconds

The time taken for the stone to hit the ground is 10 seconds.

Thus option A is the required answer.

Visit: https://brainly.com/question/13834669

solve pls brainliest

Answers

5.15, 5.2222, 5.19, 5.169



1: 103/20 2: 5.169 3: 5.19 4: 5 2/9

We have: 103/20= 5,15   ;   5 2/9= 5,(2)

So the answer is:

103/20 < 5.169 < 5.19 < 5 1/2

ok done. Thank to me :>

Determine whether a quadratic model exists for the set of values below. If​ so, write the model. f(0) = -4, f(3) = -19, f(-1) = -11

Select the correct choice below​:

A) A quadratic model does exist. It is ​f(x)= ?
B) A quadratic model does not exist.

Answers

Answer:

  A) The model exists: f(x) = -3x^2 +4x -4

Step-by-step explanation:

A quadratic model will always exist for 3 given points, provided they are not on a line. In that case, a linear model is appropriate.

Here, the slope between -1 and 0 is positive, and the slope between 0 and 3 is negative. Thus, we know these points are not collinear, and a model must exist.

The model is most easily found using a quadratic regression tool. Such is shown in the attachment. It tells us that ...

  f(x) = -3x^2 +4x -4

in a supermarket, credit card purchases have an additional charge of 8% of the purchase made. If I bought 2 suitcases that cost s / .165.60 each and paid with a credit card, how much do I have to pay?

Answers

9514 1404 393

Answer:

  357.70

Step-by-step explanation:

The final cost will be ...

  (number of suitcases) × (cost per suitcase) × (1 +8%)

  = 2(165.60)(1.08) = 357.70

Valentine's Day is coming up, so Sweet Dreams chocolate shop is ordering ribbon to decorate gift boxes. Small gift boxes use 20 inches of ribbon, while large ones use 30 inches. Sweet Dreams expects to sell 225 small boxes and 180 large boxes. If the ribbon they use is sold by the yard, how many yards of ribbon should they order?

Answers

Answer:

i think 9900

Step-by-step explanation:

225x20 = 4500

180x30 = 5400

5400+4500 = 9900

2x+5y=(-24),3x+y=(-10) solve for using elimination method

Answers

Answer:

x equals -2 and y equals−4

1+×= ???? answer it ​

Answers

Answer:

1+x=x

Step-by-step explanation:

1 is only one letter

Two trains leave towns 474 kilometers apart at the same time and travel toward each other. One train travels13 km/m faster than the other. If they meet in 2 hours, what is the rate of each train?

Answers

Answer:

112 km/h

125 km/hr

Step-by-step explanation:

Distance = time * speed

Distance  = distance train 1 + distance train 2

474 = 2(s) + 2(s + 13)

Distribute

474 = 2s + 2s + 26

Combine like terms

474 = 4s + 26

Subtract 26 from both sides

448 = 4s

Divide both sides by 4

112 = s

s = 112 km/h

s + 13 = 125 km/hr

if a chocolate cake is divided into six equal slices and each slice has 280 calories

Answers

Answer:

Whats the question?

Step-by-step explanation:

Answer:

1,680

Step-by-step explanation

6 slices each 280 calories, 280 x 6 = 1,680

Show this situation on a vertical number line

Answers

what is the situation to your question

Answer:

What is the situation?

Step-by-step explanation:

draw a diagram for this fraction

7/2​

Answers

Answer:

You can't draw a diagram for a improper

fraction

the odds against your bet are to 3. if you bet $27 and win. how much you win​

Answers

If you win, you will get eighty-one dollars ($81.00)
If you win you will get $81 because 3*27= 81

The chart shows how many people have signed up to go on a field trip each day. 62 students are allowed to go on the field trip. On which day would you expect that number to be reached?A) 8B) 9C) 10D) 11

Answers

Answer:

C

I hope it helps.

Last year at a certain high school, there were 100 boys on the honor roll and 60 girls on the honor roll. This year, the number of boys on the honor roll decreased by 11% and the number of girls on the honor roll decreased by 10%. By what percentage did the total number of students on the honor roll increase? Round your answer to the nearest tenth (if necessary).​

Answers

Answer:

-11 boys -6 girls

Step-by-step explanation:

Jason gets 15 gallons of gas for $3.90 a gallon which gives him 20 miles to the gallon. How many miles can Jason travel on one tank of Jason?

Answers

0.75 miles
15 divided by 20 as its in proportion

Answer:

0.75 mi.

Step-by-step explanation:

15/20=3.90/x

if u help me ill give u brainliest​

Answers

Answer:

150000000

Step-by-step explanation:

30x5000000=150000000

Question 2 Fill-In-The-Blank Worth 3 points)
(04.04)
Point R is at (4.1.5) and Point T is at (429) on a coordinate grid. The distance between the two points is_(Input numbers and decimal point only, such as 82)
Answer for Blank 1

Answers

Answer:

1.4

Step-by-step explanation:

in the graph, the points are 14 points apart, when the step of the graph is set to .1, if you count, they're .14 point apart, or 1.4

If here are approximately 15000 red cabs in Hong Kong. This represents approximately 80% of the total taxis. Find the total number of taxis in Hong Kong.

Answers

Answer: 18,750

Step-by-step explanation: First you divide 80 by 100, getting .80. Then you divide 15,000 by .8, getting 18,750 cars.

If you paid $160 in interest to a loan company for the use of $10000 of or 30 days, what annual simple interest rate did they charge?

Answers

Answer:A loan company charges $30 interest for a one month loan of $500. Find the annual interest rate they are charging.

Step-by-step explanation:You will earn $160 interest total over the four years. Try it Now 1. A loan company charges $30 interest for a one month loan of $500. Find the annual interest ...

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