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3 years ago

Someone please help me I'm confused

Mathematics

2 answers:

Vesnalui [34]3 years ago

8 0

Answer:

Step-by-step:

Ok. First, for volume, you do V= L x W x H.

What that means is, you would do 25cm x 20cm x 4cm. That would give you the answer.

Now for surface area, I don’t know the formula, I do it in my head. The answer for Surface Area is 1,360 cm.

I hope I helped you!

Alex777 [14]3 years ago

6 0

Answer:

Volume: 2000 cm^3 Surface Area: 1360cm^2

Step-by-step explanation:

Ok, so we know the formula for volume is length x width x height, so we can substitute in the numbers given, so we end up with:

25 x 4 x 20

when we multiply them together, we get:

2000cm^3. That's the volume.

The formula for Surface Area is:

S.A.=2(lw+wh+lh) . Now we substitute in the numbers given

S.A.=2( (25 x 4)+(4 x 20)+(25 x 20)) . Then we add and multiply, so we get:

S.A. = 1360cm^2

The Surface Area is 1360cm^2.

Hope this helped, sorry if I was wrong somewhere!

~Mschmindy

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A hiker starting at point P on a straight road wants to reach a forest cabin that is 2 km from a point Q, 3 km down the road fro

pantera1 [17]

Answer:

2.19 km

Step-by-step explanation:

If x is the distance she walks down the road before turning, then the total time is:

t = x/8 + √((3 − x)² + 2²) / 3

t = x/8 + √(9 − 6x + x² + 4) / 3

24t = 3x + 8√(13 − 6x + x²)

24t = 3x + 8(13 − 6x + x²)^½

Take derivative of both sides with respect to x.

24 dt/dx = 3 + 4(13 − 6x + x²)^-½ (-6 + 2x)

When t is a minimum, dt/dx = 0.

0 = 3 + 4(13 − 6x + x²)^-½ (-6 + 2x)

-3 = 4(13 − 6x + x²)^-½ (-6 + 2x)

3 / (6 − 2x) = 4(13 − 6x + x²)^-½

3 / (24 − 8x) = (13 − 6x + x²)^-½

(24 − 8x) / 3 = (13 − 6x + x²)^½

(24 − 8x)² / 9 = 13 − 6x + x²

576 − 384x + 64x² = 117 − 54x + 9x²

459 − 330x + 55x² = 0

Solve with quadratic formula.

x = [ 330 ± √((-330)² − 4(55)(459)) ] / 2(55)

x = (330 ± √7920) / 110

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Since 0 < x < 3, x = 2.19.

7 0

3 years ago

The accompanying data on x= head circumference z score (a comparison score with peers of the same age - a positive score suggest

djverab [1.8K]

Answer:

$r=0.77$ , $\hat{y}=770.50+39.37x$ and volume of cerebral brey matter for a child whose head circumference Z score at age 12 months was 1.9 is $\hat {y}=920.10$

Step-by-step explanation:

We attached a table below,

$(a)$ We attached a table below,

Therefore ,

correlation coefficient $r=\frac{\frac{1}{18}(21766.7)-(\frac{27.25}{18} )(\frac{13890}{18} ) }{\sqrt{\frac{1}{18} (59.8435)-(\frac{27.25}{18} )^2}\sqrt{\frac{1}{18}(10767400)-(\frac{13890}{18} )^2 } }$

$=\frac{41.04}{53.19}$

$=0.77$

$(b)$ We calculate the least squares equation.

$b_1=r(\frac{\sigma_y}{\sigma_x} )\\ =(0.77)(\frac{\sqrt{\frac{1}{18} (10767400)-(\frac{13890}{18} )^2} }{\sqrt{\frac{1}{18}(59.8435)-(\frac{27.25}{18} )^2 } } )\\ =0.77(\frac{52.15}{1.02} )\\ =0.77(51.13)\\ =39.37$

Now , calculate intercept coefficient.

$b_0=\bar{y}-r\bar{x}\\$

$=(\frac{\sum{y}}{n} )-0.77(\frac{\sum{x}}{n} )\\=(\frac{13890}{18} )-0.77(\frac{27.25}{18} )\\=771.67-1.17\\=770.50$

Therefore, the regression equation is, $\hat{y}=770.50+39.37x$

$(c)$ Find the volume of cerebral brey matter for a child whose head circumference Z score at age 12 months was 1.8

$\hat{y}=770.50+39.37x$

$=770.50+39.37(1.9)\\=770.50+74.80\\=920.10$

5 0

2 years ago

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Step2247 [10]

The Answer is -53.23

3 0

3 years ago

The mean of 19 numbers is 35.

sladkih [1.3K]

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Then we subtract the value 70 from the total sum to get the sum of the values without 70 (in order to compute the mean of these values)

Then we compute the mean.

If you have any additional questions ask.

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2 years ago

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2 years ago

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Someone please help me I'm confused​

Someone please help me I'm confused