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3 years ago

A right-angled triangle has sides of lengths (x+5)cm, (x-3)cm and 9cm. Calculate the value of x

Mathematics

1 answer:

Arturiano [62]3 years ago

6 0

Answer:

x=4.0625 cm

Step-by-step explanation:

The Pythagorean theorem states that the square of the hypotenuse of a right triangle equals the sum of the squares of the two legs.

Not knowing which is the hypotenuse, lets assume that (x+5)cm is the hypotenuse:

(x+5)^2= 9^2+(x-3)^2

(x^2+10x+25)=81+(x^2-6x+9)

x^2+10x+25=81+x^2-6x+9

16x=65

x=4.0625

Checking:

(4.0625+5)^2=9^2+(4.0625-3)^2

82.1289=82.1289

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Suppose that the population mean for income is $50,000, while the population standard deviation is 25,000. If we select a random

Fudgin [204]

Answer:

Probability that the sample will have a mean that is greater than $52,000 is 0.0057.

Step-by-step explanation:

We are given that the population mean for income is $50,000, while the population standard deviation is 25,000.

We select a random sample of 1,000 people.

Let $\bar X$ = sample mean

The z-score probability distribution for sample mean is given by;

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

where, $\mu$ = population mean = $50,000

$\sigma$ = population standard deviation = $25,000

n = sample of people = 1,000

The Z-score measures how many standard deviations the measure is away from the mean. After finding the Z-score, we look at the z-score table and find the p-value (area) associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X.

So, probability that the sample will have a mean that is greater than $52,000 is given by = P( $\bar X$ > $52,000)

P( $\bar X$ > $52,000) = P( $\frac{\bar X-\mu}{\frac{\sigma}{\sqrt{n} } }$ > $\frac{52,000-50,000}{\frac{25,000}{\sqrt{1,000} } }$ ) = P(Z > 2.53) = 1 - P(Z $\leq$ 2.53)

= 1 - 0.9943 = 0.0057

Now, in the z table the P(Z $\leq$ x) or P(Z < x) is given. So, the above probability is calculated by looking at the value of x = 2.53 in the z table which has an area of 0.9943.

Therefore, probability that the sample will have a mean that is greater than $52,000 is 0.0057.

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2 years ago

Myrna is buying a new rug for her living room. What is the area of the rug, in square feet?

likoan [24]

Answer:

The answer is 96 square feet because if you look at the first rectangle (the one on the top left), you should multiply 5 times 6 which equals 30.

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2 years ago

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NISA [10]

Answer:

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Step-by-step explanation:

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2 years ago

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The overhead reach distances of adult females are normally distributed with a mean of 205.5 and a standard deviation of 8.6 . a.

Anastasy [175]

Answer:

a) 0.073044

b) 0.75033

c) The normal distribution can be used in part (b), even though the sample size does not exceed 30 because initial population size is been distributed normally , therefore, the mean of the samples will be normally distributed regardless of their size(meaning whether the sample size is less than or equal to or exceeds 30, the sample means the mean of the samples will be normally distributed regardless of their size).

Step-by-step explanation:

The overhead reach distances of adult females are normally distributed with a mean of 205.5 and a standard deviation of 8.6 .

a. Find the probability that an individual distance is greater than 218.00 cm.

We solve using z score formula

z = (x-μ)/σ, where

x is the raw score = 218

μ is the population mean = 205.5

σ is the population standard deviation = 8.6

For x > 218

z = 218 - 205.5/8.6

z = 1.45349

Probability value from Z-Table:

P(x<218) = 0.92696

P(x>218) = 1 - P(x<218) = 0.073044

b. Find the probability that the mean for 15 randomly selected distances is greater than 204.00

When = random number of samples is given, we solve using this z score formula

z = (x-μ)/σ/√n

where

x is the raw score = 204

μ is the population mean = 205.5

σ is the population standard deviation = 8.6

n = 15

For x > 204

Hence

z = 204 - 205.5/8.6/√15

z = -0.67552

Probability value from Z-Table:

P(x<204) = 0.24967

P(x>204) = 1 - P(x<204) = 0.75033

c. Why can the normal distribution be used in part (b), even though the sample size does not exceed 30?

The normal distribution can be used in part (b), even though the sample size does not exceed 30 because initial population size is been distributed normally , therefore, the mean of the samples will be normally distributed regardless of their size(meaning whether the sample size is less than or equal to or exceeds 30, the sample means the mean of the samples will be normally distributed regardless of their size).

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3 years ago

Pamela is 8 years older that Jiri. The sum of their age is 102. What is Jiri's age?

tresset_1 [31]

Answer:

Step-by-step explanation:

102-8= 94

94/2= 47

Jiri is 47 years old.

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2 years ago