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3 years ago

How do you solve number 27 and 28

Mathematics

1 answer:

Elanso [62]3 years ago

8 0

27) if a = 1/a

multiply both sides by a

a * a = 1/a * a

a^ 2 = 1

Answer is D) 1

28)

6 x 75 = 450

7 x 80 = 560

8 x 85 = 680

9 x 90 = 810

Total all students in class = 6 + 7 + 8 + 9 = 30 students

Total score of whole class:

450 + 560 + 680 + 810 = 2500

Average = 2500 /30 = 83.3 = 83 1/3

Answer is C) 83 1/3

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A magnitude 6.7 earthquake struck the SanFernando valley region of Los Angeles in 1994, causing widespread damage. Suppose anoth

madam [21]

Answer: 2.308 .

Step-by-step explanation:

Let X denotes the number of earthquakes in SanFernando valley region of Los Angeles in 1994.

Given: $\mu=17.6$

Probability is 0.87 that there will be at least 15 earthquakes .

i.e. $P(X\geq15)=0.87$

$\Rightarrow\ P(\dfrac{X-\mu}{\sigma}\geq\dfrac{15-17.6}{\sigma})=0.87\\\\ \Rightarrow\ P(Z\geq\dfrac{-2.6}{\sigma})=0.87\ \ \ [Z=\dfrac{X-\mu}{\sigma}]$

Z-value corresponding to p-value 0.87 is -1.1263 .

So, $\dfrac{-2.6}{\sigma}=-1.1263$

$\sigma= \dfrac{-2.6}{-1.1263}\approx2.308$

Hence, the required standard deviation = 2.308 .

4 0

3 years ago

Find the area of the polygon

AlekseyPX

Answer:

The answer is $383m^{2}$ .

To find the area of a rectangle, we multiply the length of the rectangle by the width of the rectangle.

Please Mark Brainliest If This Helped!

7 0

2 years ago

25 POINTS AVAILABLE

myrzilka [38]

Answer:

$\large\boxed{1.\ (-3, 0),\ r = 3}\\\boxed{2.\ (x+4)^2+(y-3)^2=36}\\\boxed{3.\ (x-2)^2+(y-1)^2=(\sqrt{34})^2}$

Step-by-step explanation:

The equation of a circle in standard form:

$(x-h)^2+(y-k)^2=r^2$

(h, k) - center

r - radius

1. We have the equation:

$(x+3)^2+y^2=9\\\\(x-(-3))^2+(y-0)^2=3^2$

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2. We have the center (-4, 3) and the radius r = 6. Substitute:

$(x-(-4))^2+(y-3)^2=6^2\\\\(x+4)^2+(y-3)^2=36$

3. We have the endpoints of the diameter: (-1, 6) and (5, -4).

Midpoint of diameter is a center of a circle.

The formula of a midpoint:

$\left(\dfrac{x_1+x_2}{2};\ \dfrac{y_1+y_2}{2}\right)$

Substitute:

$h=\dfrac{-1+5}{2}=\dfrac{4}{2}=2\\\\k=\dfrac{6+(-4)}{2}=\dfrac{2}{2}=1$

The center is in (2, 1).

The radius length is equal to the distance between the center of the circle and the endpoint of the diameter.

The formula of a distance between two points:

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

Substitute the coordinates of the points (2, 1) and (5, -4):

$r=\sqrt{(5-2)^2+(-4-1)^2}=\sqrt{3^2+(-5)^2}=\sqrt{9+25}=\sqrt{34}$

Finally we have:

$(x-2)^2+(y-1)^2=(\sqrt{34})^2$

7 0

3 years ago

Plzzzzzzzzzzzzzzzzzzz help

liq [111]

Answer:

Step-by-step explanation:

1/2 b h

1/2×10×5=25

so i guess the ans is 25 thats all I know

u take 1/2 base ×height

4 0

3 years ago

Read 2 more answers

Describe how to use a tens fact to find the difference for 15-8=7

prisoha [69]

You can do 15-5=10 and then you have 3 left to subtract. Which means 10-3=7

8 0

3 years ago

Read 2 more answers