What is the area of the following circle? D = 2

Mathematics

2 answers:

Vladimir79 [104]3 years ago

8 0

Answer:

$\pi \: {r}^{2} = \pi \: { \frac{d}{4} }^{2}$

Plug the formula in to your calculator

lbvjy [14]3 years ago

6 0

The area of the circle would be 3.14

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What is the equation of the line that passes through (-3, -1) and has a slope of 2/5? Put your answer in slope-intercept form.

Zanzabum

Hi there!

The general formula of A line in slope-intercept form is the following:
$y = mx + n$

In this formula m represents the slope of the line. Therefore, we can conclude that m = 2/5.
$y = \frac{2}{5} x + n$

We also know that the line passes through the point (-3, -1) and we can therefore substitute this coordinate into the formula of the line.
x = -3 and y = -1

$- 1 = \frac{2}{5} \times - 3 + n$

Multiply first.
$- 1 = - 1\frac{1}{5} + n$

And finally add 1 1/5 to both sides of the equation.
$\frac{1}{5} = n$

We can now switch sides.
$n = \frac{1}{5}$

Now we've found our value of n, which we can substitute into the formula of our line. Hence, in slope-intercept form, we find the following:
$y = \frac{2}{5} x + \frac{1}{5}$

7 0

3 years ago

The mean of a population is 74 and the standard deviation is 15. The shape of the population is unknown. Determine the probabili

Lena [83]

Answer:

a) 0.0548 = 5.48% probability of a random sample of size 36 yielding a sample mean of 78 or more.

b) 0.9858 = 98.58% probability of a random sample of size 150 yielding a sample mean of between 71 and 77.

c) 0.5793 = 57.93% probability of a random sample of size 219 yielding a sample mean of less than 74.2

Step-by-step explanation:

To solve this question, we need to understand the normal probability distribution and the central limit theorem.

Normal Probability Distribution:

Problems of normal distributions can be solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the z-score of a measure X is given by:

$Z = \frac{X - \mu}{\sigma}$

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value 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. Subtracting 1 by the p-value, we get the probability that the value of the measure is greater than X.

Central Limit Theorem

The Central Limit Theorem estabilishes that, for a normally distributed random variable X, with mean $\mu$ and standard deviation $\sigma$ , the sampling distribution of the sample means with size n can be approximated to a normal distribution with mean $\mu$ and standard deviation $s = \frac{\sigma}{\sqrt{n}}$ .