This has to be done within a hour, and I’m really stuck

a pyramid whose altitude is 5ft weighs 800lbs. at what distance from its vertex must it be cut by a plane parallel to its base s

slavikrds [6]

A structure which has a square base and four triangular sides meeting at a point is called pyramid.

At distance of 3.97 feet from its vertex , pyramid is cut by plane so that the two solids of equal weight will be formed.

It is assumed that weight of pyramid is proportional to its volume.

So, $w = k V$ , where V is volume of original pyramid and v is volume of small pyramid and k is constant.

Let us consider that at h distance, pyramid is cut from its vertex. So a small pyramid is also formed.

Assume that base area of original pyramid is A and base of small pyramid is a.

Volume of original pyramid is, $V= \frac{1}{3} *A* 5$

So, weight of original pyramid, $W = k *(\frac{1}{3} *A* 5) = 800$

Volume of small pyramid is, $v = \frac{1}{3}* a* h$

So, weight of small pyramid, $w = k*(\frac{1}{3}* a* h)=400$

Since, base and height of small pyramid and original pyramid are in proportion.

So, $\frac{a}{A} = (\frac{h}{5}) ^{2}$

$a = (\frac{h}{5} )^{2}A$

Substituting value of a in equation $k*(\frac{1}{3}* a* h)=400$

So, $k*(\frac{1}{3}* \frac{h^{2} }{25}A * h)=400$

$(k*\frac{1}{3}* A*5)*\frac{1}{5} *\frac{h^{2} }{25} * h)=400$

Since, $(k *\frac{1}{3} *A* 5) = 800$ , substitute in above equation.

So, $800*\frac{h^{3} }{125}=400\\\\h^{3}=\frac{125}{2}\\\\h=\sqrt[\frac{1}{3} ]{62.5}\\\\h=3.97 feet$

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Rosa ran the hurdles in 58.32 seconds. maya ran the hurdles in 54.078 seconds. what is the difference between the two times? 3.9

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Answer:

Step-by-step explanation: 4.242

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1 year ago

Explain how showing fractions with models in a number line are alike and different.

zhenek [66]

Showing fractions with models is giving a visual and sometimes can be easier to process.They also can be in picture form or other.Ex. A piece of pizza cut into fourths.

Showing fractions on a number line is also giving a visual but still allows you to add and subtract using numbers if that makes sense.Ex.
. ----.-------.
1/3 2/3 3/3

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3 years ago

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Which inequality is shown in the graph?

sergij07 [2.7K]

Answer:

The answer to your question is: letter C

Step-by-step explanation:

Data

Find the Parabola's equation and express the equation as an inequality.

Vertex = (0, -5)

Equation

(x- h) ² = 4p(y - k)

x² = y + 5

y = x² - 5

But, we need the area upper the parabola, then

y ≥ x² - 5

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3 years ago

Please help, I’ll mark your answer as brainliest!

statuscvo [17]

Answer:

$(x-230)^2+(y-220)^2=6100$

Step-by-step explanation:

The equation for a circle is $(x-h)^2+(y-k)^2=r^2$ , where $(h,k)$ is the vertex of the circle and $r$ is the radius. Immediately, since the center of the circle is given, we know what $h$ and $k$ are. $h$ is 230 and $k$ is 220.

The only thing we need to find is the radius, which will just be the distance from the center (230,220) to a point on the circumference (170,170). The distance between them can be calculated using the distance formula, which is really just the Pythagorean Theorem rearranged. The formula states that $d=\sqrt{x^2+y^2}$ , where $x$ is the change in the x-coordinates of the two points and $y$ is the change in the y-coordinates of the two points. Plug-in $x$ for 60 and $y$ for 50 to get $d=\sqrt{50^2+60^2}$ . Solve for $d$ , arriving at $\sqrt{6100}$ . Therefore, the radius of the circle is $\sqrt{6100}$ .

Finally, we have all of the components to create the equation of the circle. Plug-in 230 for $h$ , 220 for $k$ , and $\sqrt{6100}$ for $r$ .

The equation of the circle will be $(x-230)^2+(y-220)^2=6100$ .

Hope this helps :)

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2 years ago