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attashe74 [19]
3 years ago
14

If y=24 when x=21, find y when x is 18

Mathematics
1 answer:
ludmilkaskok [199]3 years ago
5 0

Answer:20.571

Step-by-step explanation:

x:y = 21: 24=7:8

8x=7y

y=8x/7

When x=18

y=8*18/7

y=20.571

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Is anyone can do this?
exis [7]

Answer:

Surface of35,875.86 cm^2

Voliume of 234,671.58 cm^3

Long and painful calculations

Ok, this is going to take some time. The volume is the sum of all the solids, minus the half cylinder that makes the "tunnel" beneath it. That said, we can split the item into 3 main shapes, and the cylinder: The pyramid in the top left, the square based prism below the pyramid, and the trapezoid prism to the right. I edited a bit the image with paint to add measurements. It's paint so quality is what it is and deal with comic sans as a font.

Let's find the total surface first. We have the surface of the four faces of the pyramid, which are triangles of base 54 and height (red line)\sqrt{36^2+(\frac{54}2)^2} =\sqrt{2025}=45cm, givins us a total area of 4\times \frac{bh}2 = 2\times 45\times 54 = 4860 cm^2

We add the two lateral faces of the left prism: they are two rectangles of side length 70 and 54, for a total area of 2(70)(54) = 7580 cm^2

Take the rectangle to the side of the prism, of sides 54 and 70-34 = 36, giving an area of 54\times 36 = 1944 cm^2

Pick the inclined "roof" of the right prism, again a rectangles, sides 54 and 61: surface is 3294 cm^2

Two side faces of the right building: first pick the height (magenta line), with pythagorean theorem again, equal to \sqrt{ 61^2-11^2} = \sqrt{3600} = 60 cm. The surface becomes 2 \frac{(B+b)h}2 = (34+45)(60)= 4740 cm^2

Missing the short sides and the half cylinder making the gallery. The sides - if you imagine un-hinging one and attaching to the bottom of the other - will make a rectangle of sides (45+70) cm and 54 cm with a circular hole in the middle. surface is (45+70)\times54 - \pi(54/2)^2 =3920.94 cm^2.

Finally, the half cylinder. It's a "rectangle) tall (60+54) cm - the length of the whole contraption, and long half the circle, or 27\pi. It's surface is  (60+54)\times\27\pi = 9664.92 cm^2

Done with surfaces. At this point we just add everything together. Grab a calculator and start adding up, if I didn't miss anything the total surface will be 35875.86 cm^2

Volumes now. You wished this was over? I totally did.

Bulk of the calculations are done luckly. It's just to cut and paste here and there.

Pyramid first. We know the side length, we know the height, volume is the usual formula

\frac 13l^2h = \frac 13 54^2\times 36= 33,048 cm^3

Cube beneath. This one is also easy Sides are 54cm, 54cm and 70cm, volume is their product:

54*54*70= 204,120 cm^3

Side prism now: again base surface times height, let's use the trapezoid as a base since we already have the area from above:

A_th = 2370\times54 = 127,980 cm^3

From this we take <u>half</u> a cylinder of radius 27 tall as the whole structure is long. \frac12 \pi r^2h = \frac12 \pi (27)^2(60+54) = 130,476.42 cm^3

We're done. Let's add the volume of the first 3 solids and subtract the last one - hope you have your calculator handy, to get in total a volume of 234,671.58 cm^3

Double and triple check numbers, even if I rand them with excel.

6 0
3 years ago
A city manager wants
ValentinkaMS [17]

Answer:

A is the answer

Step-by-step explanation:

5 0
3 years ago
Simplify the expressions 4x+2x-15+3×
mylen [45]

Answer:

9x - 15

Step-by-step explanation:

Using the addition of like terms we know that 4x + 2x = 6x, and 6x + 3x = 9x, and then we just put -15 at the end and we end up with 9x - 15

3 0
3 years ago
What is the density of an object 8g /cm3 and mass is 200g
pav-90 [236]
The density would be 1560.7 lb/cu ft.
3 0
3 years ago
The bases of an isosceles trapezoid are represented by 4x and 2x.. The height of the trapezoid is represented by (x − 6). Which
rusak2 [61]
The formula for solving the area of a trapezoid is shown below:
Area = ((a+b)/2 ) * h
where "a" and "b" for the base and "h" for the height
 a = 4x
b = 2x
c = (x-6) 

The solution for the polynomial expression is shown below:
Area = (4x + 2x)/2  * (x-6)
Area = 6x/2 * (X-6)
Area = 3X * (X-6)
Area = 3X²  - 18X

The answer is 3X² - 18X.
8 0
3 years ago
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