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3 years ago

How do you write 18.9 in scientific notation?

Mathematics

2 answers:

vesna_86 [32]3 years ago

8 0

Answer:

1.89*10^1

Step-by-step explanation:

move the decimal once to the left

gavmur [86]3 years ago

5 0

Answer:

1.89 × 10^1

Step-by-step explanation:

I think im right

If i am can i get brainly crown pls?

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A square is cut in half on the diagonal creating two equal triangles each triangle has an area of 0.72 square units what is the

Katyanochek1 [597]

In a square all 4 sides are equal, so when you cut it along the diagonal to make a triangle, both the base and the height of the triangle would be the same.

The area of a triangle is found by the formula 1/2 x base x height

Since the base and height are the same the formula becomes Area = 1/2 x S^2 ( where S is the length of a side).

The area is given as 0.72 square units.

Now you have 0.72 = 1/2 x S^2

First multiply both sides by 2:

1.44 = S^2

To find S, take the square root of both sides:

S = √1.44

S = 1.2

The side length is 1.2 units.

7 0

3 years ago

See image attached below keeeeeeeeeeeeeeeeeeeed

emmasim [6.3K]

Answer:

.13%

68.26%

2.28%

47.72%

49.87%

34.13%

Step-by-step explanation:

1.) standardize by subtracting the mean and dividng by the standard deviation

(625-1000)/125= -3

go to a ztable to get .0013 or (1-.9987)

this is equal to .13%

2.)

875<x<1125

standardize both seperately and subtract them

(875-1000)/125= -1 whose probability is .1587 (or 1-.8413)

(1125-1000)/125= 1 whose probability is .8413

.8413-.1587= 68.26%

3.)

Find the probability that someone paid less than 1250 and take its compliment

(1250-1000)/125= 2 which has a probability of .9772

take its compliment (1-.9772)= .0228= 2.28%

4.)

Same process as question 2

(750-1000)/125= -2 which has a probability of (1-.9772) = .0228

(1000-1000)/125= 0 which has a probability of .5

.5-.0228= .4772= 47.72%

5.) same deal as the previous question

(625-1000)/125= -3 which has a probability of (1-.9987)= .0013

(1000-1000)/125= 0 which has a probability of .5

.5-.0013= .4987= 49.87%

6.)same deal the previous question

(875-1000)/125= -1 which has a probability of (1-.8413)=.1587

(1000-1000)/125= 0 which has a probability of .5

.5-.1587= .3413= 34.13%

4 0

3 years ago

Birth weights of babies born to full-term pregnancies follow roughly a Normal distribution. At Meadowbrook Hospital, the mean we

Marina86 [1]

Answer:

Required Probability = 0.1283 .

Step-by-step explanation:

We are given that at Meadow brook Hospital, the mean weight of babies born to full-term pregnancies is 7 lbs with a standard deviation of 14 oz.

Firstly, standard deviation in lbs = 14 ÷ 16 = 0.875 lbs.

Also, Birth weights of babies born to full-term pregnancies follow roughly a Normal distribution.

Let X = mean weight of the babies, so X ~ N( $\mu = 7 lbs , \sigma^{2} = 0.875^{2} lbs$ )

The standard normal z distribution is given by;

Z = $\frac{Xbar-\mu}{\frac{\sigma}{\sqrt{n} } }$ ~ N(0,1)

where, X bar = sample mean weight

n = sample size = 4

Now, probability that the average weight of the four babies will be more than 7.5 lbs = P(X bar > 7.5 lbs)

P(X bar > 7.5) = P( $\frac{Xbar-\mu}{\frac{\sigma}{\sqrt{n} } }$ > $\frac{7.5-7}{\frac{0.875}{\sqrt{4} } }$ ) = P(Z > 1.1428) = 0.1283 (using z% table)

Therefore, the probability that the average weight of the four babies will be more than 7.5 lbs is 0.1283 .

8 0

3 years ago

A beach has to enclose a rectangular area, because some endangered species are nesting there. They have 200 feet of rope to rope

kkurt [141]

Area is equal to length times width. The perimeter (the amount of rope) has to equal twice the length added to twice the width so we're left with:
A = l * w
200 = 2l + 2w
solve for either l or w
l = 100 - w
plug into the area equation to get one equation with two variables
A = w(100 - w)
A = -w^2 + 100w
take the derivative
A' = -2w + 100
set the derivative equal to zero
0 = -2w + 100
2w = 100
w = 50
This is the width that maximizes the area
with a width of 50, the length must also be 50 to have a perimeter of 200
therefore, they can rope up to 50 * 50 = 2500 ft^2

6 0

3 years ago

Hi!! please answer he questions below using inverse operations! (if you show work i will give you brainiest!)

solniwko [45]

Answer:

13) 90-18 = 72

14) 108/9 = 12

15) 66+34 = 100

16) 7*8 = 56

Step-by-step explanation:

All you need to do is take the second term of each equation and move it to the other side. So for number 16 we just need to move the 8 from the left to the right. This is as simple as multiplying both sides by 8 to get:

8*(56/8) = 8(7)

56 = 8*7

And that would be the answer to number 16!

5 0

3 years ago