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Andreyy89
3 years ago
12

A circular plate has circumference 21.4 inches. What is the area of this​ plate? Use 3.14 for pi. The area of this plate is abou

t nothing square inches.
Mathematics
1 answer:
kolezko [41]3 years ago
8 0

Answer: Area of circular plate is 36.5 square inches

Step-by-step explanation:

The formula for determining the circumference of a circle is expressed as

Circumference = 2πr

Where

r represents the radius of the circle.

π is a constant whose value is 3.14

From the information given,

Circumference of circular plate = 21.4 inches. Therefore

2 × 3.14 × r = 21.4

6.28r = 21.4

r = 21.4/6.28

r = 3.41 inches

The formula for determining the area of a circle is expressed as

Area = πr²

Area of circular plate = 3.14 × 3.41² = 36.5 square inches

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Suppose that 10% of the undergraduates at a certain university are foreign students, and that 25% of the graduate students are f
Deffense [45]

Answer:

0.6154 = 61.54% probability that the student is an undergraduate

Step-by-step explanation:

Conditional Probability

We use the conditional probability formula to solve this question. It is

P(B|A) = \frac{P(A \cap B)}{P(A)}

In which

P(B|A) is the probability of event B happening, given that A happened.

P(A \cap B) is the probability of both A and B happening.

P(A) is the probability of A happening.

In this question:

Event A: Foreign

Event B: Undergraduate.

There are four times as many undergraduates as graduate students

So 4/5 = 80% are undergraduate students and 1/5 = 20% are graduate students.

Probability the student is foreign:

10% of 80%

25% of 20%. So

P(A) = 0.1*0.8 + 0.25*0.2 = 0.13

Probability that a student is foreign and undergraduate:

10% of 80%. So

P(A \cap B) = 0.1*0.8 = 0.08

What is the probability that the student is an undergraduate?

P(B|A) = \frac{P(A \cap B)}{P(A)} = \frac{0.08}{0.13} = 0.6154

0.6154 = 61.54% probability that the student is an undergraduate

8 0
3 years ago
What is the area of<br> this figure?
n200080 [17]

Answer:

243 cm^2 + 108 cm^2 = 351 cm^2

Step-by-step explanation:

So, we have a rectangle and two triangles, we know all the sides or angles.

Rectangle: with 9 cm lenght 15cm + 12 cm = 27 cm

Formula: A=wl -> A=9*27 = 243 cm^2

Trianlge: A=ab/2

Angle 90°

Side A 12 cm

Side B 18 cm - 9 cm = 9 cm

A=ab/2=12·9/2=54 cm times 2 (for the opposite side) = 108 cm^2 = 351 cm^2

6 0
2 years ago
According to Scarborough Research, more than 85% of working adults commute by car. Of all U.S. cities, Washington, D.C., and New
tamaranim1 [39]

Answer:

The 99% confidence interval for the mean commute time of all commuters in Washington D.C. area is (22.35, 33.59).

Step-by-step explanation:

The (1 - <em>α</em>) % confidence interval for population mean (<em>μ</em>) is:

CI=\bar x\pm z_{\alpha /2}\frac{\sigma}{\sqrt{n}}

Here the population standard deviation (σ) is not provided. So the confidence interval would be computed using the <em>t</em>-distribution.

The (1 - <em>α</em>) % confidence interval for population mean (<em>μ</em>) using the <em>t</em>-distribution is:

CI=\bar x\pm t_{\alpha /2,(n-1)}\frac{s}{\sqrt{n}}

Given:

\bar x=27.97\\s=10.04\\n=25\\t_{\alpha /2, (n-1)}=t_{0.01/2, (25-1)}=t_{0.005, 24}=2.797

*Use the <em>t</em>-table for the critical value.

Compute the 99% confidence interval as follows:

CI=27.97\pm 2.797\times\frac{10.04}{\sqrt{25}}\\=27.97\pm5.616\\=(22.354, 33.586)\\\approx(22.35, 33.59)

Thus, the 99% confidence interval for the mean commute time of all commuters in Washington D.C. area is (22.35, 33.59).

8 0
3 years ago
Radioactive Decay Beginning with 16 grams of a radioactive element whose half -life is 30 years ,the mass y(in grams) remaining
Flura [38]

Answer:

the equation should be corrected to fit the data of the problem.  With the corrected equation a mass of 0.5 grams remains after 150 years

Step-by-step explanation:

for the mass y( in grams)

y=23* (1/2)^(t/45), t ≥ 0.

the initial mass is at t=0 , then

y= 23 grams  → should be 16 grams

half-life from the equation = 45 years → should be 30 years

the correct equation should be

y=16*(1/2)^(t/30), t ≥ 0

then after 150 years  → t= 150

y=16*(1/2)^(150/30)= 16*(1/2)^5 = 16/32 = 0.5 grams

then a mass of 0.5 grams remains after 150 years

5 0
3 years ago
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Answer: 4

Step-by-step explanation:

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3 0
3 years ago
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