Ask question

Ask question

All categories

Anuta_ua [19.1K]

1 year ago

14

A bridge builder wants to know the width of a river. He stands at point A along the river. He picks a point C directly across th

e river. He then walks downstream 90 feet from point A to point B. From point B, he sites C and determines the angle between the bank and point C (θ), to be 43º. What is the width of the river?

1 answer:

Maurinko [17]1 year ago

8 0

<span>width = 90 tan43 degrees = about 84 feet </span>

You might be interested in

6. Charlie can spend up to $8 on lunch. He wants to buy a tuna sandwich, a bottle of

PilotLPTM [1.2K]

Answer:

The maximum number of pounds of potato salad that Charlie can buy is 0.375

Step-by-step explanation:

see the attached figure to better understand the problem

Let

a ----> the cost of one tuna sandwich

b ----> the cost of a bottle of apple juice

c ----> the cost per pound of potato salad

x ----> pounds of potato salad

we have

$a=\$4.25$

$b=\$2.25$

$c=\$4.00/lb$

we know that

He wants to buy a tuna sandwich, a bottle of apple juice, and x pounds of potato salad and can spend up to $8

The inequality that represent this situation is

$a+b+cx \leq 8$

substitute the given values

$4.25+2.25+4.00x \leq 8$

Solve for x

Combine like terms

$6.50+4.00x \leq 8$

Subtract 6.50 both sides

$4.00x \leq 8-6.50$

$4.00x \leq 1.50$

Divide by 4 both sides

$x \leq 1.50/4.00$

$x \leq 0.375\ lbs$

therefore

The maximum number of pounds of potato salad that Charlie can buy is 0.375

3 0

2 years ago

A website advertises job openings on its website, but job seekers have to pay to access the list of job openings. The website re

nataly862011 [7]

Answer:

The 90% confidence interval would be given by (57.006;62.994)

Step-by-step explanation:

Previous concepts

The margin of error is the range of values below and above the sample statistic in a confidence interval.

Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".

A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".

$\bar X=60$ represent the sample mean

$\mu$ population mean (variable of interest)

$\sigma=10$ represent the population standard deviation

n=30 represent the sample size

Assuming the X follows a normal distribution

$X \sim N(\mu, \sigma=10)$

The sample mean $\bar X$ is distributed on this way:

$\bar X \sim N(\mu, \frac{\sigma}{\sqrt{n}})$

The confidence interval on this case is given by:

$\bar X \pm z_{\alpha/2}\frac{\sigma}{\sqrt{n}}$ (1)

The next step would be find the value of $\z_{\alpha/2}$ , $\alpha=1-0.90=0.1$ , $\alpha/2 =0.05$ and $z_\alpha/2=1.64$

Using the normal standard table, excel or a calculator we see that:

$z_{\alpha/2}=1.64$

Since we have all the values we can replace:

$60 - 1.64\frac{10}{\sqrt{30}}=57.006$

$60 + 1.64\frac{10}{\sqrt{30}}=62.994$

So on this case the 90% confidence interval would be given by (57.006;62.994)

5 0

2 years ago

Sarah kicked a ball in the air. The function

Aleksandr-060686 [28]

Answer: The ball hits the ground at 5 s

Step-by-step explanation:

The question seems incomplete and there is not enough data. However, we can work with the following function to understand this problem:

$f=30 t- 6t^{2}$ (1)

Where $f$ models the height of the ball in meters and $t$ the time.

Now, let's find the time $t$ when the ball Sara kicked hits the ground (this is when $f=0 m$ ):

$0=30 t- 6t^{2}$ (2)

Rearranging the equation:

$6t^{2}-30 t=0$ (3)

Dividing both sides of the equation by $6$ :

$t^{2}-5 t=0$ (4)

This quadratic equation can be written in the form $at^{2}+bt+c=0$ , and can be solved with the following formula:

$t=\frac{-b \pm \sqrt{b^{2}-4ac}}{2a}$ (5)

Where:

$a=1$

$b=-5$

$c=0$

Substituting the known values:

$t=\frac{-(-5) \pm \sqrt{(-5)^{2}-4(1)(0)}}{2(1)}$ (6)

Solving we have the following result:

$t=5 s$ This means the ball hit the ground 5 seconds after it was kicked by Sara.

6 0

2 years ago

A fence is guarding off a vegetable garden in the form of a rectangle. It has one side that is 10m greater than the other side.

DanielleElmas [232]

Answer:

The length of the fence needed to surround this garden is 188 meters.

Step-by-step explanation:

Given : A fence is guarding off a vegetable garden in the form of a rectangle. It has one side that is 10 m greater than the other side.

To find : The length of the fence needed to surround this garden if the area of the vegetable garden is 2184 m² ?

Solution :

Let the one side of rectangle be 'x'.

Then the other side is 'x+10'.

The area of the rectangle is 2184 m²,

i.e. $x(x+10)=2184$

$x^2+10x-2184=0$

Solve by middle term split,

$x^2+52x-42x-2184=0$

$x(x+52)-42(x+52)=0$

$(x+52)(x-42)=0$

$x=-52,42$

Reject negative value,

The side of the rectangle is 42 m.

The other side is 42+10=52 m

The perimeter of the rectangle is $P=2(l+b)$

$P=2(42+52)$

$P=2(94)$

$P=188$

Therefore, the length of the fence needed to surround this garden is 188 meter.

5 0

1 year ago

A geometry teacher asked Radric to define "parallel lines." Radric said that parallel lines are lines in a plane that do not hav

UkoKoshka [18]

Answer: The answer is Yes.

Step-by-step explanation: Given in the question that Radric was asked to define "parallel lines" and he said that parallel lines are lines in a plane that do not have any points in common. We are to decide whether Radric's definition is valid or not.

Parallel lines are defined as lines in a plane which never meets or any two lines in a plane which do not intersect each other at any point are called parallel.

Thus, Radric's definition is valid.

6 0

2 years ago

Read 2 more answers