Which transformation best describes the image of a object viewed through a microscope?

A building engineer analyzes a concrete column with a circular cross section. The circumference of the column is 18 \pi18π18, pi

Whitepunk [10]

Answer:

$A=81\pi $ m^2$

Step-by-step explanation:

Circumference of the column $=18\pi $ meters$

Circumference of a circle $=2\pi r$

Therefore:

$2\pi r =18\pi $ meters\\2r=18\\r=18 \div 2\\$Radius, r=9 meters$

Area of a Circle $=\pi r^2$

Since radius of the cross section of the column =9 meters

Area of the cross section of the column

$=\pi *9^2\\=81\pi $ m^2$

5 0

2 years ago

10 times as many as 1 ten is ______ tens.

anyanavicka [17]

Same 10 tens I guess

5 0

2 years ago

A baker makes apple tarts and apple pies each day. Each tart, t, requires 1 apple, and each pie, p, requires 8 apples. The baker

siniylev [52]

Answer: t<40

8p+<184

Step-by-step explanation:

3 0

2 years ago

Read 2 more answers

The average time an individual reads online national news reports is 49 minutes. Assume the standard deviation is 16 minutes and

Alexus [3.1K]

Answer:

11.70% probability someone will spend no more than 30 minutes reading online national news reports.

Step-by-step explanation:

Problems of normally distributed samples can be solved using the z-score formula.

In a set with mean $\mu$ and standard deviation $\sigma$ , the zscore 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 pvalue, we get the probability that the value of the measure is greater than X.

In this problem, we have that:

$\mu = 49, \sigma = 16$

What is the probability someone will spend no more than 30 minutes reading online national news reports?

This is at most 30 minutes, so 30 or less minutes. This is the pvalue of Z when X = 30.

So

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

$Z = \frac{30 - 49}{16}$

$Z = -1.19$

$Z = -1.19$ has a pvalue of 0.1170.

So there is a 11.70% probability someone will spend no more than 30 minutes reading online national news reports.

4 0

2 years ago

John wants to send a letter to peter who lives on tesla street john does not remember the house number however he knows that it

Serggg [28]

Answer: 137 letters.

Step-by-step explanation:

The data is:

The number has 4 digits.

The number is a multiple of 5

The number is a multiple of 7

The last digit is a 0.

Then, let's find all the possible numbers that met these conditions.

Our number can be formed with 4 digits, A, B, C and D.

D is the last one, so we have D = 0.

So the number is: ABC0

We know that all the numbers that end with 0 are multiples of 5, so that condition does not matter.

Now, a number is divisible by 7 if:

Take the last digit of the number, double it and subtract it to the remaining number, if the result is multiple of 7, then the initial number is a multiple of 7.

In this case the last digit is 0, so when we double it and subtract it, we actually are not changing the other 3 digits.

Then we have that:

ABC must be a multiple of 7.

So now our problem reduces to find the number of 3-digit numbers that are multiples of 7.

The first multiple of 7 that has 3 digits is:

7*15 = 105.

And the largest possible 3 digit number is 999, now let's try to divide it by 7 to see if this is also a multiple of 7.

999/7 = 142.7

the quotient is not integer, so 999 is not a multiple of 7.

The next option is 998, we can do the same here:

998/7 = 142.6

And so on, we will find that the largest 3 digit multiple of 7 is:

994, such that:

7*152=994.

Then we have:

Smallest: 7*15 = 105

Largest: 7*152 = 994.

Then the number of multiples of 7 between 999 and 100 will be equal to the difference between the quotients between the multples and 7.

105/7 = 15

994/7 = 152

152 - 15 = 137

So we have 137 multiples of 7 with 3 digits.

Then we have 137 4-digit numbers, that end with a zero and also are divisible by 5 and 7.

So John must send 137 letters if he wants to be shure that Peter will get the card.

5 0

2 years ago