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3 years ago

Answers for both boxes please

Mathematics

1 answer:

sleet_krkn [62]3 years ago

7 0

Answer:

x = -5 y = -3

Step-by-step explanation:

-3x + 2y = 9

multiply the 2nd equation by 3 to set it up for elimination

3(x - 3y)= 3(4)

3x-9y = 12

so now combine both to add

-3x + 2y = 9

3x - 9y = 12

Adding both gives you

-7y = 21

divide both by -7 and you get

y = -3

and you substitute y back into equation to get x

x - 3 (-3) = 4 gives you

x + 9 = 4

x = 4 - 9

x = -5

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The bottom part of this block is a rectangular prism. The top part is a square pyramid. You want to cover the block entirely wit

Umnica [9.8K]

Answer:

Hence required paper for entire shape will be L[L+2(2H+H1)] Sq.cm

Step-by-step explanation:

Given:

A block with rectangular prism at bottom and square pyramid at top.

To Find:

Paper required to cover whole block

Solution:

We know that block consist of two different shapes as prism and pyramid.

So paper covering will be for surface.

hence we required surface area for rectangular prism and square pyramid.

(Refer the attachment)

Now only outer surface should be consider in order to cover the shape.

for square pyramid its length and breadth will be the same .

let L be length and B be breadth and h be height

So total no.of faces will be 6 but on top there is prism placed so top surface will be neglected for the calculations.

Hence No.of faces will be 5.

So total surface area for square pyramid will be

=L*W+2(L*H+W*H)

Here L=W as it is square pyramid

=L^2+4(L*H)

Now for the Prism surface it will have 4 triangles placed on with base as length of pyramid(as shown in fig) and height be H1

So Total area for Prism will be

=4( Area of triangles)

=4*1/2*base*height)

=2*base *height

=2*L*H1

So required Paper will be

Total surface area=Surface are of pyramid+ Area of 4 triangles.

=L^2+4(L*H)+2*L*H1

=L[L+2(2H+H1)].

4 0

3 years ago

What is the surface area of the figure shown? (use 3.14 for pi)

SpyIntel [72]

This is a combination of the formula of several figures.

The first one is the bottom of the cylinder AKA a circle.
The second one is the cylinder - the bottom and the top.
The third one is a cone without a bottom.

The first one can be written like this: r^2*3.14 where r is the radius of the circle
The second one is written like this: 2*3.14*r*h where r is the radius, and h the height
The third one is written like this: l*r*3.14

After this you just have to input the values.
bottom cylinder Cone (Use calculator if possible)
(3^2*3.14)+(2*3.14*3*5)+(6*3*3.14)=
28.26 + 94.2 + 56.52 = 178.98 in^2

The correct answer is 178.98 in^2.
Youre welcome.

EXTRA:

If youre wondering how to find the different formulas, you can search for the full formula, then remove the parts you do not need, by matching them with the formula of the part you want to remove.

Example:
Cylinder:
SA = 2(pi r 2) + (2 pi r)* h
In this case, i didnt need the top and bottom, then i look for the formula of a circle.
Circle SA = pi r^2

Is this anywhere in the cylinder? Yes! The first part.
Then we are left with:
2 + (2 pi r)*h
But that 2 looks strangely placed, and with some reason, one quickly understands that it means "top AND bottom", but since we removed the circle surface, we have to remove that part too.
So the final result of the formula is:
2 pi r h

4 0

4 years ago

Please help on this one i appreciate it!! :)

leonid [27]

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3 0

3 years ago

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Martina needs to make a total of 40 deliveries this week. so far she has completed 12 of them. what percentage of her total deli

Luda [366]

Answer: 10 percent

Step-by-step explanation: