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3 years ago

A cylinder has a diameter of 40 feet and a height of 32 feet. What is the surface area of the cylinder? Express the answer in

Mathematics

1 answer:

mafiozo [28]3 years ago

5 0

Answer:

$6524.51 ft^2$

Step-by-step explanation:

The surface area of a cylinder is given as;

$SA = 2\pi rh + 2\pi r^2$

where r = radius

h = height

The cylinder has a height of 32 feet and a diameter of 40 feet. This means that the radius is:

40 / 2 = 20 feet

The surface area is therefore:

$SA = (2*\pi* 20 * 32) + (2*\pi *20^2)\\\\SA = 4021.24 + 2513.27\\\\SA = 6524.51 ft^2$

The surface area of the cylinder is $6524.51 ft^2$ .

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Which equation represents the polar form of x² + (y + 4)² = 16?

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$x^2+y^2=r^2\hspace{5em}x=r\cos(\theta )\hspace{5em}y=r\sin(\theta ) \\\\[-0.35em] ~\dotfill\\\\ x^2+(y+4)^2=16\implies x^2+\stackrel{binomial~expansion}{y^2+8y+16}=16 \\\\\\ \underset{x^2+y^2}{r^2} + 8(~\underset{8y}{r\sin(\theta )}~)=16-16\implies r^2+8r\sin(\theta)=0 \\\\\\ r^2=-8r\sin(\theta )\implies \cfrac{r^2}{r}=-8\sin(\theta )\implies r=-8\sin(\theta )$

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2 years ago

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Vladimir79 [104]

Answer:

the thrid one

Step-by-step explanation:

5 0

3 years ago

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The GCF of any two even numbers is always even. Determine whether the statement is true or false. If true, explain why. If false

choli [55]

True because<span> the common factor to both numbers would be an even number.

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3 years ago

A data mining routine has been applied to a transaction dataset and has classified 88 records as fraudulent (30 correctly so) an

Firlakuza [10]

Answer:

The classification matrix is attached below

Part a

The classification error rate for the records those are truly fraudulent is 65.91%.

Part b

The classification error rate for records that are truly non-fraudulent is 96.64%

Step-by-step explanation:

The classification matrix is obtained as shown below:

The transaction dataset has 30 fraudulent correctly classified records out of 88 records, that is, 30 records are correctly predicted given that an instance is negative.

Also, there would be 88 - 30 = 58 non-fraudulent incorrectly classified records, that is, 58 records are incorrectly predicted given that an instance is positive.

The transaction dataset has 920 non-fraudulent correctly classified records out of 952 records, that is, 920 records are correctly predicted given that an instance is positive.

Also, there would be 952 - 920 = 32 fraudulent incorrectly classified records, that is, 32 records incorrectly predicted given that an instance is negative.

That is,

Predicted value

Active value Fraudulent Non-fraudulent

Fraudlent 30 58

non-fraudulent 32 920

The classification matrix is obtained by using the information related to the transaction data, which is classified into fraudulent records and non-fraudulent records.

The error rate is obtained as shown below:

The error rate is obtained by taking the ratio of $\left( {b + c} \right)(b+c)$ and the total number of records.

The classification matrix is, shown above

The total number of records is, $30 + 58 + 32 + 920 = 1,040$

The error rate is,

$\begin{array}{c}\\{\rm{Error}}\,{\rm{rate}} = \frac{{b + c}}{{{\rm{Total}}}}\\\\ = \frac{{58 + 32}}{{1,040}}\\\\ = \frac{{90}}{{1,040}}\\\\ = 0.0865\\\end{array}$

The percentage is $0.0865 \times 100 = 8.65$

(a)

The classification error rate for the records those are truly fraudulent is obtained by taking the rate ratio of b and $\left( {a + b} \right)(a+b)$ .

The classification error rate for the records those are truly fraudulent is obtained as shown below:

The classification matrix is, shown above and in the attachment

The error rate for truly fraudulent is,

$\begin{array}{c}\\FP = \frac{b}{{a + b}}\\\\ = \frac{{58}}{{30 + 58}}\\\\ = \frac{{58}}{{88}}\\\\ = 0.6591\\\end{array}$

The percentage is, $0.6591 \times 100 = 65.91$

(b)

The classification error rate for records that are truly non-fraudulent is obtained by taking the ratio of d and $\left( {c + d} \right)(c+d)$ .

The classification error rate for records that are truly non-fraudulent is obtained as shown below:

The classification matrix is, shown in the attachment

The error rate for truly non-fraudulent is,

$\begin{array}{c}\\TP = \frac{d}{{c + d}}\\\\ = \frac{{920}}{{32 + 920}}\\\\ = \frac{{920}}{{952}}\\\\ = 0.9664\\\end{array}$

The percentage is, $0.9664 \times 100 = 96.64$

6 0

3 years ago

Sophia vegetable garden is divided into 12 equal sections.She plants carrots in 8 of section .Write two fractions that are equiv

stepan [7]

The unsimplified fraction is 8/12 which can be reduced to 2/3

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3 years ago

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