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2 years ago

How do you know pi x r x r x h

1 answer:

4 0

V= πr^2h

This is the formula for volume of a cylinder. The volume formula builds off the area formula. Where area is more 2-dimensional, volume is 3-dimensional. You can think of a flat sheet of paper for area (2-dimensional) and a solid box for volume (3-dimensional).

Usually your teacher would give the formulas when starting this section of math. From there, either keep a list of needed formulas in your math folder for easy reference, or try to memorize the formulas for the current section of math you are working on. Some teachers allow formula reference sheets and some do not.

Hope this answers your question! :)

You might be interested in

For how many integer values of n will the value of the expression 4n + 7 be an integer greater than 1 and less than 200?

Morgarella [4.7K]

Answer:

Step-by-step explanation:

We are asked that the value of (4n + 7) will be an integer > 1 and < 200, for how many integer values of n.

So, equating (4n + 7) with 200 we can get the value.

4n + 7 = 200

⇒ 4n = 193

⇒ n = 48.25

Hence, the value of n will be the largest integer less than 48.25.

Therefore, the number of integer values of n will be 48. (Answer)

3 0

3 years ago

.........................................................................................................

erastova [34]

Answer:

I have no clue... I'm very sorry...

Step-by-step explanation:

4 0

2 years ago

ANSWER ASAP!! Find the area of a triangle with legs that are: 12 m, 15 m, and 9 m.

Setler79 [48]

Answer:

Step-by-step explanation:

<h3>METHOD 1:</h3>

You can use the Heron's formula:

$A=\sqrt{p(p-a)(p-b)(p-c)}$

where

<em>p</em><em> - half of perimeter</em>

<em>a, b, c</em><em> - lengths of sides</em>

We have

$a=12m;\ b=15m;\ c=9m$

Calculate:

$p=\dfrac{12+15+9}{2}=\dfrac{36}{2}=18\ (m)\\\\A=\sqrt{18(18-12)+(18-15)(18-9)}\\\\A=\sqrt{(18)(6)(3)(9)}\\\\A=\sqrt{2916}\\\\A=54\ (m^2)$

<h3>METHOD 2:</h3>

Let's check that it is not a right triangle.

If the sum of the squares of the two shorter sides is equal to the square of the longest side, then this triangle is rectangular.

We have

$9m < 12m$

Check:

$9^2+12^2=81+144=225\\15^2=225$

This is a right trianglr wherew 9m and 12m are legs and 15m is a hypotenuse.

The formula of an area of a right triangle is:

$A=\dfrac{ab}{2}$

Substitute:

$A=\dfrac{(9)(12)}{2}=\dfrac{108}{2}=54\ (m^2)$

6 0

3 years ago

Jasmine is riding on a carousal. She is sitting 9.5 feet from the center and it takes 20 seconds to

rusak2 [61]

Answer:

<em>2.983 </em>ft/sec

Step-by-step explanation:

Given that

Distance between center and Jasmine riding on a carousal = 9.5 feet

Time taken to complete one rotation = 20 seconds

To find:

Jasmine's linear speed = ?

Solution:

Number of revolutions per minute = $\frac{60}{20} = 3$

Formula for linear speed is given as:

$v=\dfrac{2\pi}{60}\cdot r\cdot RPM$

Where $r$ is the radius of circular path and

$RPM$ is the number of revolutions per minute.

$v=\dfrac{2\pi}{60}\times 9.5 \times 3\\\Rightarrow v=\dfrac{\pi}{10}\times9.5 \\\Rightarrow v = \bold{2.983\ ft/sec}$

Therefore, the linear speed is <em>2.983 ft/sec.</em>

5 0

3 years ago

How to do this plastic help

liraira [26]

Answer:

39 degrees

Step-by-step explanation:

by seeing the diagram in the attachment, we can see that the angles UWV and VWX are on straight line or, their sum makes 180 degrees.

we also know that sum of the angles in a triangle is 180 degrees.

by using the first statement,

UWV + VWX = 180

UWV + 6x-3 = 180

UWV = 180+3-6x

= 183-6x

by using second statement,

UWV+WVU+VUW=180

substituting the values,

183-6x+2x+5+x+13=180

201-3x=180

substracting 180 from both sides,

21=3x

dividing both the sides by 3,

7=x

the angle VWX=6x-3

substituting 7=x,

VWX=6(7)-3= 39.

4 0

3 years ago