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3 years ago

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Robert is lying on the ground, looking at the top of a flagpole. The angle of elevation to the top of the flagpole is 25°. What

is the height of the flagpole if the distance from his eyes at the ground to the base of the flagpole is 200 ft? PLEASE HELPPPPPP

1 answer:

enyata [817]3 years ago

8 0

Answer: r =15 degrees

Step-by-step explanation:

Measure the length of the shadow of the yardstick and the flagpole. Since the ends of the shadows are in line with the tops of the respective objects and the sun, the lengths of their shadows are proportional. Multiply the shadow ratio by the height of the yardstick (yh) to get the height of the flagpole.

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Find the locus of a point such that the sum of its distance from the point ( 0 , 2 ) and ( 0 , -2 ) is 6.

jok3333 [9.3K]

Answer:

$\displaystyle \frac{x^2}{5}+\frac{y^2}{9}=1$

Step-by-step explanation:

We want to find the locus of a point such that the sum of the distance from any point P on the locus to (0, 2) and (0, -2) is 6.

First, we will need the distance formula, given by:

$d=\sqrt{(x_2-x_1)^2+(y_2-y_1)^2}$

Let the point on the locus be P(x, y).

So, the distance from P to (0, 2) will be:

$\begin{aligned} d_1&=\sqrt{(x-0)^2+(y-2)^2}\\\\ &=\sqrt{x^2+(y-2)^2}\end{aligned}$

And, the distance from P to (0, -2) will be:

$\displaystyle \begin{aligned} d_2&=\sqrt{(x-0)^2+(y-(-2))^2}\\\\ &=\sqrt{x^2+(y+2)^2}\end{aligned}$

So sum of the two distances must be 6. Therefore:

$d_1+d_2=6$

Now, by substitution:

$(\sqrt{x^2+(y-2)^2})+(\sqrt{x^2+(y+2)^2})=6$

Simplify. We can subtract the second term from the left:

$\sqrt{x^2+(y-2)^2}=6-\sqrt{x^2+(y+2)^2}$

Square both sides:

$(x^2+(y-2)^2)=36-12\sqrt{x^2+(y+2)^2}+(x^2+(y+2)^2)$

We can cancel the x² terms and continue squaring:

$y^2-4y+4=36-12\sqrt{x^2+(y+2)^2}+y^2+4y+4$

We can cancel the y² and 4 from both sides. We can also subtract 4y from both sides. This leaves us with:

$-8y=36-12\sqrt{x^2+(y+2)^2}$

We can divide both sides by -4:

$2y=-9+3\sqrt{x^2+(y+2)^2}$

Adding 9 to both sides yields:

$2y+9=3\sqrt{x^2+(y+2)^2}$

And, we will square both sides one final time.

$4y^2+36y+81=9(x^2+(y^2+4y+4))$

Distribute:

$4y^2+36y+81=9x^2+9y^2+36y+36$

The 36y will cancel. So:

$4y^2+81=9x^2+9y^2+36$

Subtracting 4y² and 36 from both sides yields:

$9x^2+5y^2=45$

And dividing both sides by 45 produces:

$\displaystyle \frac{x^2}{5}+\frac{y^2}{9}=1$

Therefore, the equation for the locus of a point such that the sum of its distance to (0, 2) and (0, -2) is 6 is given by a vertical ellipse with a major axis length of 3 and a minor axis length of √5, centered on the origin.

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3 years ago

Read 2 more answers

This is for my math review due tomorrow I need help!!

Snowcat [4.5K]

Z is greater than or equal to 7.

you would put a 7 near the front of the number line and put a colored in circle above it. then you would draw a line from the circle to the other end of the line

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3 years ago

Alexander deposited money into his retirement account that is compounded annually at an interest rate of 7%.

anzhelika [568]

Tow rates are equivalent if tow initial investments over a the same time, produce the same final value using different interest rates.

For the annually rate we have that:
$V_{0} =(1+ i_{a} ) ^{1}$
Where
$V_{0}$ = initial investment.
$i_{a}$ = annually interest rate in decimal form.
And the exponent (1) represents the full year.

For the quarterly interest rate we have that:
$V_{0} =(1+ i_{q} ) ^{4}$
Where
$V_{0}$ = initial investment.
$i_{q}$ = quarterly interest rate in decimal form.
And the exponent (4) the 4 quarters in the full year.

Since the rates are equivalent if tow initial investments over a the same time, produce the same final value, then
$(1+ i_{a} )=(1+ i_{q} ) ^{4}$
Notice that we are not using the initial investment $V_{0}$ since they are the same.

The first thin we are going to to calculate the equivalent quarterly rate of the 7% annually rate is converting 7% to decimal form
7%/100 = 0.07
Now, we can replace the value in our equation to get:
$(1+0.07)=(1+ i_{q} ) ^{4}$
$1.07=(1+ i_{q} ) ^{4}$
$\sqrt[4]{1.07} =1+ i_{q}$
$i_{q} = \sqrt[4]{1.07} -1$
$i_{q} =0.017$
Finally, we multiply the quarterly interest rate in decimal form by 100% to get:
(0.017)(100%) = 1.7%
We can conclude that Alexander is wrong, the equivalent quarterly rate of an annually rate of 7% is 1.7% and not 2%.

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3 years ago

We define a bow-tie quadrilateral as a quadrilateral where two sides cross each other. An example of a bow-tie quadrilateral is

aleksandrvk [35]

Answer:

70/5985

Step-by-step explanation:

We know that a quadrilateral needs to have four vertices (or points on the circle). There are always two ways to link the cross — horizontally or vertically. Using my limited knowledge of combinations, we know that choosing four points out of seven equals 35. Multiplying the two ways to connect those lines (again, horizontally and vertically) makes 35*2 = 70 "bow-tie quadrilaterals" that can be formed on the circle using four points. There are 5985 ways four chords can be chosen out of twenty-five chords because C(25,4) equals 5985, so the probability is 70/5985... and then we just need to simplify that fraction.

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3 years ago

Tom,Scott and dawn sold cookies at the school fair.

aleksklad [387]

First of all work out how many tom and scott sold.
tom sold 60% of 90 cookies which is 54.
scott sold 2/3 of 150 cookies which is 100.
altogether the three of them sold 54+100+46 cookies which is 200.
Dawn sold 46 of these 200 cookies. To work out the percentage we have both the numbers to get 23 out of 100. We halved those numbers because a percentage is out of 100 we halved it to get it out of 100.
so 23 out of 100 is 23% so dawn sold 23%of the cookies.

Hope this helps :)

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3 years ago