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3 years ago

13

The surface are of a cube is 54 square centimeters. The area of a face on the cube is 9 square centimeters. What is the volume,

in cubic centimeters

1 answer:

Lera25 [3.4K]3 years ago

6 0

The volume of the cube is 27 cubic feet.

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Given the triangle below what would be the measure in degrees of

alexira [117]

Answer:

∠B = 52°

Step-by-step explanation:

Since we know that the sum of all inner angles of the triangle equal to 180°, then we can make the following equation,

5x + 3x + 2x + 20 = 180

10x = 180 - 20

10x = 160

x = 160 / 10

x = 16

Since we know that ∠B = (2x + 20)°, we can calculate the following

∠B = (2x + 20)°

∠B = (2(16) + 20)°

∠B = (32 + 20)°

∠B = 52°

5 0

3 years ago

The South Coast Air Basin (Los Angeles, Orange, and San Bernardino counties) does not meet the air quality standards for carbon

Archy [21]

Answer:

0.2225 gr/mile

Step-by-step explanation:

Let's work out first the amount of CO sent out in 1990.

The population we estimated in 12.5 million people with a total of driven miles per year of about

12.5 million*8,700 = 108,750 million miles.

With an CO emission factor of 0.9 g per mile, we would have a total of CO emitted rounding 0.9*180,750 = 97,875 million grams

Now, we must estimate the population for 2020.

Since we are assuming an exponential growth, the population in year t is given by a function

$\bf P(t)= Ce^{kt}$

where C and k are constants to be determined.

We can take 1980 as year 0. This way calculations are lighter. 1990 is year 10 and 2020 is year 20.

So P(0) = 10.3 and C=10.3

So far we have

$\bf P(t)= 10.3e^{kt}$

Given that P(10)=12.5

$\bf 10.3e^{k*10}=12.5\rightarrow e^{10k}=\frac{12.5}{10.3}=1.21359\rightarrow \\10k=log(1.21359)\rightarrow k=0.01936$

And the function that models the population growth is

$\bf P(t)= 10.3e^{0.01936t}$

We need P(20)

$\bf P(20)= 10.3e^{0.01936*20}=10.3e^{0.38717}=15.17\;million$

If the miles driven per person per year remains constant at 8700 mi/yr.person, then we have a total miles driven of

15.17*8,700=131,979 million miles, so the CO emitted would be 0.9*131,979=118,781.1 million grams.

The 30% of the CO sent out in 1990 is 0.3*97,875=29,362.5 million grams.

We must reduce 118,781.1 down to 29,362.5

Hence the new CO emission factor would be

29,362.5/131,979 = 0.2225 gr/mile

6 0

3 years ago

A rectangle is constructed with its base on theâ x-axis and two of its vertices on the parabola yequals=2525minusâxsquared2. wha

Nina [5.8K]

You should have drawn1 - x-axis and y-axis in light pencil.2 - graphed a down-facing parabola with the top of the frown on the y-axis at y = 2. It should be crossing the x-axis at ±√2. This should be in dark pencil or another color.3 - In dark pencil or a completely new color, draw a rectangle with one of the horizontal sides sitting on top of the x-axis and the other horizontal side touching the parabola at each of the top corners of the rectangle. The rectangle will have half of its base in the positive x-axis and the other half on the negative x-axis. It should be split right down the middle by the y-axis. So each half of the base we will say is "x" units long. So the whole base is 2x units long (the x units to the right of the y-axis, and the x units to the left of the y-axis) I so wish I could draw you this picture... In the vertical direction, both vertical edges are the same length and we will call that y. The area that we want to maximize has a width 2x long, and a height of y tall. So A = 2xy This is the equation we want to maximize (take derivative and set it = 0), we call it the "primary equation", but we need it in one variable. This is where the "secondary equation" comes in. We need to find a way to change the area formula to all x's or all y's. Since it is constrained to having its height limited by the parabola, we could use the fact that y=2 - x2 to make the area formula in only x's. Substitute in place of the "y", "2 - x2" into the area formula. A = 2xy = 2x(2 - x2) then simplify A = 4x - 2x3 NOW you are ready to take the deriv and set it = 0 dA/dx = 4 - 6x2 0 = 4 - 6x2 6x2 = 4 x2 = 4/6 or 2/3 So x = ±√(2/3) Width remember was 2x. So the width is 2[√(2/3)]Height is y which is 2 - x2 = 2 - 2/3 =4/3

6 0

4 years ago

A square is cut from a rectangle. The side length of the square is half of the unknown width w. The area of the shaded region is

Virty [35]

Answer:

See below

Step-by-step explanation:

<u>The side of the square is w/2, then its area is:</u>

A = (w/2)² = w²/4

<u>The shaded area is the difference of areas of the rectangle and the square:</u>

14w - w²/4 = 84

<u>This can be simplified:</u>

56w - w² = 336
w² - 56w + 336 = 0

8 0

3 years ago

Which of the following is NOT a true statement?

Mandarinka [93]

B. Angle 2 and angle seven are actually alternate exterior angles.

4 0

3 years ago

Read 2 more answers