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2 years ago

How many rectangular faces does a pentagonal pyramid have?

Mathematics

2 answers:

Evgen [1.6K]2 years ago

7 0

My best answer 5 faces.

puteri [66]2 years ago

4 0

Answer:

My best answer 5 faces.

Step-by-step explanation:

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"three times a number is greater than or equal to 12 and less than 21"

Diano4ka-milaya [45]

Answer:

The required inequality is: 12 ≤ 3x < 21

Step-by-step explanation:

We are given: three times a number is greater than or equal to 12 and less than 21

We need to answer following questions:

1) The inequality translated in numerical form

Let number = x

12 ≤ 3x < 21

2) Your work solving the inequality

We need to find value of x. Divide the inequality by x

4 ≤ x < 7

3) The solution graphed on a number line

It is shown in figure attached.

4) The solution in set notation

The set notation is: Considering x belongs to natural numbers N

{∀ x|x∈N, 4 ≤ x < 7}

5) The solution in interval notation

The interval notation is: [4,7)

because we have 4 less than equal to x and x is less than 7

8 0

2 years ago

The liquid base of an ice cream has an initial temperature of 86°C before it is placed in a freezer with a constant temperature

Karolina [17]

The temperature of the ice cream 2 hours after it was placed in the freezer is 37.40 °C

From Newton's law of cooling, we have that

$T_{(t)}= T_{s}+(T_{0} - T_{s})e^{kt}$

Where

$(t) = \ time$

$T_{(t)} = \ the \ temperature \ of \ the \ body \ at \ time \ (t)$

$T_{s} = Surrounding \ temperature$

$T_{0} = Initial \ temperature \ of \ the \ body$

$k = constant$

From the question,

$T_{0} = 86 ^{o}C$

$T_{s} = -20 ^{o}C$

∴ $T_{0} - T_{s} = 86^{o}C - -20^{o}C = 86^{o}C +20^{o}C$

$T_{0} - T_{s} = 106^{o} C$

Therefore, the equation $T_{(t)}= T_{s}+(T_{0} - T_{s})e^{kt}$ becomes

$T_{(t)}=-20+106 e^{kt}$

Also, from the question

After 1 hour, the temperature of the ice-cream base has decreased to 58°C.

That is,

At time $t = 1 \ hour$ , $T_{(t)} = 58^{o}C$

Then, we can write that

$T_{(1)}=58 = -20+106 e^{k(1)}$

Then, we get

$58 = -20+106 e^{k(1)}$

Now, solve for $k$

First collect like terms

$58 +20 = 106 e^{k}$

$78 =106 e^{k}$

Then,

$e^{k} = \frac{78}{106}$

$e^{k} = 0.735849$

Now, take the natural log of both sides

$ln(e^{k}) =ln( 0.735849)$

$k = -0.30673$

This is the value of the constant $k$

Now, for the temperature of the ice cream 2 hours after it was placed in the freezer, that is, at $t = 2 \ hours$

From

$T_{(t)}=-20+106 e^{kt}$

Then

$T_{(2)}=-20+106 e^{(-0.30673 \times 2)}$

$T_{(2)}=-20+106 e^{-0.61346}$

$T_{(2)}=-20+106\times 0.5414741237$

$T_{(2)}=-20+57.396257$

$T_{(2)}=37.396257 \ ^{o}C$

$T_{(2)} \approxeq 37.40 \ ^{o}C$

Hence, the temperature of the ice cream 2 hours after it was placed in the freezer is 37.40 °C

Learn more here: brainly.com/question/11689670

6 0

2 years ago

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Need helpppppppppp please

aleksley [76]

Adding the two equations
3x + 6y + 3x - 6y = 36+0
6x = 36
x = 6
.
subtracting second equation from first
(3x + 6y ) - (3x-6y) =36 -0
12y = 36
y = 3
.
therefore
x = 6 and y = 3
(6,3)

8 0

2 years ago

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the curved surface of a cylindrical surface is 704 cm square calculate the height when the radius is 8cm

AlexFokin [52]

Answer:

CSA of cylinder = 704cm²

We know that

CSA of cylinder = 2πrh

or 2πrh = 704

or, 2*22/7 *8 *h = 704 ( since r=8cm)

or, 352h = 704*7

or, h = 4928/352 = 14cm

7 0

2 years ago

Plssssssssssssssssssssss helpppp

morpeh [17]

Answer:

I think its 2 kg anyone correct me if I'm wrong!

5 0

2 years ago

Read 2 more answers