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2 years ago

8. In AABC, LA is a right angle and mzB = 45°. Find BC.

Mathematics

1 answer:

Margaret [11]2 years ago

7 0

Answer:

BC = 11 $\sqrt{2}$

Step-by-step explanation:

using the sine ratio in the right triangle and the exact value

sin45° = $\frac{1}{\sqrt{2} }$ , then

sin 45° = $\frac{opposite}{hypotenuse}$ = $\frac{AC}{BC}$ = $\frac{11}{BC}$ = $\frac{1}{\sqrt{2} }$ ( cross- multiply )

BC = 11 $\sqrt{2}$

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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

Carlos walk to school on the 14th of 20 days in February which value is equivalent to the fraction of school days in February th

Lady bird [3.3K]

Answer:

$\dfrac{7}{10}$

Step-by-step explanation:

Given that,

Carlos walk to school on the 14th of 20 days in February.

We need to find the equivalent to the fraction of school days in February that Carlos walk to school.

Required percentage is given by :

$\%=\dfrac{14}{20}\times 100\\\\=14\times 5\\\\=70\%$

$=\dfrac{7}{10}$

So, the required fraction is equal to $\dfrac{7}{10}$ .

6 0

2 years ago

Can someone help with that?<br><br>if x+y=2, calculate: <br>P=4x (x-3)+4y(y-3)+8xy

olganol [36]

Answer:

Step-by-step explanation:

P = 4x(x - 3) + 4y(y - 3) + 8xy

= 4x² - 12x + 4y² - 12y + 8xy

= (4x² + 8xy + 4y²) - (12x + 12y)

= 4(x² + 2xy + y²) - 12(x + y)

= 4(x + y)² - 12(x + y)

x+y =2 ⇒ P = 4.2² - 12.2 = 16 - 24 = -8

6 0

3 years ago

Which face has an area of 28 cm

Neko [114]

Answer:

trapezium?

Step-by-step explanation:

6 0

3 years ago

Glenna says that the height of her house is 1 yard is her claim reasonable

muminat

No, her answer is not reasonable because one yard is equal to 3 feet.

4 0

3 years ago

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