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3 years ago

8 grade math dont really uderstand it so please explain also

Mathematics

1 answer:

pishuonlain [190]3 years ago

5 0

Answer: Girls weekly: 25; Girls never:40; boys yearly: 25; boys never: 20; boys total:80 monthly total: 30

Step-by-step explanation:

You have to figure it out by adding or subtracting where ever it needs to be like in girls weekly you have to subtract the weekly total and the boys weekly to figure it out.

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A composite figure is shown.

VikaD [51]

The surface area of the pyramid is 60 square feet

The surface area of the square prism is 480 square feet

The surface area of the cube is 180 square feet

The total surface area is 720 square feet

<h3>Area of Composite figures</h3>

From the question, we are to calculate the surface area of each part of the composite figure

For the cube

Surface area of a cube is given by

$S = 6l^{2}$

Where $l$ is the length of a side

But only have 5 surfaces of the cube are part of the composite figure

∴ Surface area of the cubic part of the figure = $5l^{2}$

From the given information,

$l = 6 \ feet$

∴ Surface area of the cubic part of the figure = 5 × 6²

Surface area of the cubic part of the figure= 180 square feet

For the square prism

The surface area of a square prism is given by the formula,

$S = 2l^{2} + 4lh$

Where $l$ is the length of the sides and

$h$ is the height

But the <u>square surfaces</u> are not part of the surface of the figure

∴ Surface area of the square prism in the figure = $2l^{2} + 4lh - 2l^{2}$

Surface area of the square prism in the figure = $4lh$

From the given information,

$l = 6 \ feet$

$h = 20 \ feet$

Thus,

Surface area of the square prism part of the figure = 4×6×20

Surface area of the square prism part of the figure = 480 square feet

For the pyramid

The pyramid is a square pyramid

The surface area of a square pyramid is given by

$S = l^{2} + 2l\sqrt{\frac{l^{2} }{4}+h ^{2} }$

Where $l$ is the base length

and $h$ is the height of the prism

But the <u>square base</u> is not part of the surface of the figure

∴ Surface area of the pyramid part of the figure = $l^{2} + 2l\sqrt{\frac{l^{2} }{4}+h^{2} }\ - ( l^{2})$

Surface area of the pyramid part of the figure = $2l\sqrt{\frac{l^{2} }{4}+h^{2} }$

From the given information,

$l = 6 \ feet$

$h = 4 \ feet$

∴ Surface area of the pyramid part of the figure = $2(6)\sqrt{\frac{6^{2} }{4}+4^{2} }$

= $12\sqrt{\frac{36 }{4}+16}$

= $12\sqrt{9+16 }$

= $12\sqrt{25}$

= 12 × 5

= 60 square feet

Hence, the surface area of the pyramid is 60 square feet

Thus,

The total surface area = 180 square feet + 480 square feet + 60 square feet

The total surface area = 720 square feet

Hence, the total surface area is 720 square feet

Learn more on Calculating area of composite figures here: brainly.com/question/13175744

#SPJ1

4 0

2 years ago

What is the perimeter of the triangle shown on the coordinate plane,to the nearest tenth of a unit ?

ollegr [7]

Answer:

25.6 units

Step-by-step explanation:

From the figure we can infer that our triangle has vertices A = (-5, 4), B = (1, 4), and C = (3, -4).

First thing we are doing is find the lengths of AB, BC, and AC using the distance formula:

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

where

$(x_1,y_1)$ are the coordinates of the first point

$(x_2,y_2)$ are the coordinates of the second point

- For AB:

$d=\sqrt{[1-(-5)]^{2}+(4-4)^2}$

$d=\sqrt{(1+5)^{2}+(0)^2}$

$d=\sqrt{(6)^{2}}$

$d=6$

- For BC:

$d=\sqrt{(3-1)^{2} +(-4-4)^{2}}$

$d=\sqrt{(2)^{2} +(-8)^{2}}$

$d=\sqrt{4+64}$

$d=\sqrt{68}$

$d=8.24$

- For AC:

$d=\sqrt{[3-(-5)]^{2} +(-4-4)^{2}}$

$d=\sqrt{(3+5)^{2} +(-8)^{2}}$

$d=\sqrt{(8)^{2} +64}$

$d=\sqrt{64+64}$

$d=\sqrt{128}$

$d=11.31$

Next, now that we have our lengths, we can add them to find the perimeter of our triangle:

$p=AB+BC+AC$

$p=6+8.24+11.31$

$p=25.55$

$p=25.6$

We can conclude that the perimeter of the triangle shown in the figure is 25.6 units.

6 0

3 years ago

A poll of all 2000 students in a high school found that 94% of its students owned cell phones.

LekaFEV [45]

Answer: F. Parameter, because the data set of all 2000 students in a high school is a population.

Step-by-step explanation:

Parameters is a variable or measure that is calculated from the entire population of data while a statistic is done from a sample of the data.

The question notes that the poll was done on <u>all 2,000</u> students in a high school. This means that the poll is a Parameter because it was done on the entire population of the high school.

7 0

3 years ago

What is the exact distance from (-5, 1) to (3,0)?

Vlada [557]

Distance is calculated by the square root of (x2-x1)^2 + (y2-y1)^2

We simply substitute the values into this formula

Square root of (3--5)^2 + (0-1)^2

Which is 8

8 0

3 years ago

HELP

stira [4]

You would just do 5.7-8.1, which is -3.6 degrees Celcius. Hope I helped!

5 0

3 years ago