All categories

3 years ago

How does the volume of a cylinder change when its diameter is halved? Explain Please.

1 answer:

8 0

The answer is: it will decrease 4 times.

Let d be diameter and h height of a cylinder

The volume of a cylinder is:
V1 = π * (d/2)² * h = π * d²/4 * h = π * d² * h / 4
If diameter is halved, the volume is:
V2 = π * ((d/2)/2)² * h = π * (d/4)² * h = π * d²/16 * h = π * d² * h / 16

Now, let's compare them:
V1 / V2 = (π * d² * h / 4) / (π * d² * h / 16)

π * d² * h can be cancelled out:
V1 / V2 = (1/4) / (1/16) = (1/4) * 16 = 16/4 = 4

Therefore, the volume of the smaller cylinder will decrease 4 times.

You might be interested in

Find the domain of the graphed function

andreev551 [17]

Answer:

Step-by-step explanation:

Because the lowest point in the X coordinate is -4 and the highest point is 9.

6 0

3 years ago

What percent of 120 is 42

poizon [28]

35%.

42/120 = 0.35.

0.35 X 100 = 35. That tells us 42 is 35% of 120.

6 0

3 years ago

Please help :) I have no clue & math isn’t my strong subject.

melisa1 [442]

Equation of a line that is perpendicular to given line is $y=\frac{-7}{4} x+\frac{7}{4}$ .

Equation of a line that is parallel to given line is $y=\frac{4}{7} x-\frac{69}{7}$ .

Solution:

Given line $y=\frac{4}{7} x+4$ .

Slope of this line, $m_1$ = $\frac{4}{7}$

$$\text{Slope of perpendicular line} = \frac{-1}{\text{Slope of the given line} }$

$$m_2=\frac{-1}{m_1}$

$$=\frac{-1}{\frac{4}{7} }$

Slope of perpendicular line, $m_2=\frac{-7}{4}$

Passes through the point (–7, 5). Here $x_1=-7, y_1=5$ .

Point-slope formula:

$y-y_1=m(x-x_1)$

$$y-(-7)=\frac{-7}{4} (x-5)$

$$y+7=\frac{-7}{4} x+\frac{35}{4}$

Subtract 7 from both sides, we get

$$y=\frac{-7}{4} x+\frac{7}{4}$

Equation of a line that is perpendicular to given line is $y=\frac{-7}{4} x+\frac{7}{4}$ .

To find the parallel line:

Slopes of parallel lines are equal.

$m_1=m_3$

$$m_3=\frac{4}{7}$

Passes through the point (–7, 5). Here $x_1=-7, y_1=5$ .

Point-slope formula:

$$y-(-7)=\frac{4}{7} (x-5)$

$$y+7=\frac{4}{7} x-\frac{20}{7}$

Subtract 7 from both sides,

$$y=\frac{4}{7} x-\frac{69}{7}$

Equation of a line that is parallel to given line is $y=\frac{4}{7} x-\frac{69}{7}$ .

7 0

3 years ago

You are designing a miniature golf course and need to calculate the surface area and volume of many of the objects that will be

laiz [17]

a. To solve the first part, we are going to use the formula for the surface area of a sphere: $A=4 \pi r^2$
where
$A$ is the surface area of the sphere
$r$ is the radius of the sphere
We know from our problem that $r=5ft$ ; so lets replace that value in our formula:
$A=4 \pi (5ft)^2$
$A=314.16ft^2$

To solve the second part, we are going to use the formula for the volume of a sphere: $V= \frac{4}{3} \pi r^3$
Where
$V$ is the volume of the sphere
$r$ is the radius
We know form our problem that $r=5ft$ , so lets replace that in our formula:
$V= \frac{4}{3} \pi (5ft)^3$
$V=523.6ft^3$

We can conclude that the surface area of the sphere is 314.16 square feet and its volume is 523.6 cubic feet.

b. To solve the first part, we are going to use the formula for the surface area of a square pyramid: $A=a^2+2a \sqrt{ \frac{a^2}{4} +h^2}$
where
$A$ is the surface area
$a$ is the measure of the base
$h$ is the height of the pyramid
We know form our problem that $a=8ft$ and $h=12ft$ , so lets replace those value sin our formula:
$A=(8ft)^2+2(8ft) \sqrt{ \frac{(8ft)^2}{4} +(12ft)^2}$
$A=266.39ft^2$

To solve the second part, we are going to use the formula for the volume of a square pyramid: $V=a^2 \frac{h}{3}$
where
$V$ is the volume
$a$ is the measure of the base
$h$ is the height of the pyramid
We know form our problem that $a=8ft$ and $h=12ft$ , so lets replace those value sin our formula:
$V=(8ft)^2 \frac{(12ft)}{3}$
$V=256ft^3$

We can conclude that the surface area of our pyramid is 266.39 square feet and its volume is 256 cubic feet.

c. To solve the first part, we are going to use the formula for the surface area of a circular cone: $A= \pi r(r+ \sqrt{h^2+r^2}$
where
$A$ is the surface area
$r$ is the radius of the circular base
$h$ is the height of the cone
We know form our problem that $r=5ft$ and $h=8ft$ , so lets replace those values in our formula:
$A= \pi (5ft)[(5ft)+ \sqrt{(8ft)^2+(5ft)^2}]$
$A=226.73ft^2$

To solve the second part, we are going to use the formula for the volume os a circular cone: $V= \pi r^2 \frac{h}{3}$
where
$V$ is the volume
$r$ is the radius of the circular base
$h$ is the height of the cone
We know form our problem that $r=5ft$ and $h=8ft$ , so lets replace those values in our formula:
$V= \pi (5ft)^2 \frac{(8ft)}{3}$
$V=209.44ft^3$

We can conclude that the surface area of our cone is 226.73 square feet and its surface area is 209.44 cubic feet.

d. To solve the first part, we are going to use the formula for the surface area of a rectangular prism: $A=2(wl+hl+hw)$
where
$A$ is the surface area
$w$ is the width
$l$ is the length
$h$ is the height
We know from our problem that $w=6ft$ , $l=10ft$ , and $h=16ft$ , so lets replace those values in our formula:
$A=2[(6ft)(10ft)+(16ft)(10ft)+(16ft)(6ft)]$
$A=632ft^2$

To solve the second part, we are going to use the formula for the volume of a rectangular prism: $V=whl$
where
$V$ is the volume
$w$ is the width
$l$ is the length
$h$ is the height
We know from our problem that $w=6ft$ , $l=10ft$ , and $h=16ft$ , so lets replace those values in our formula:
$V=(6ft)(16ft)(10ft)$
$V=960ft^3$

We can conclude that the surface area of our solid is 632 square feet and its volume is 960 cubic feet.

e. Remember that a face of a polygon is a side of polygon.
- A sphere has no faces.
- A square pyramid has 5 faces.
- A cone has 1 face.
- A rectangular prism has 6 faces.
Total faces: 5 + 1 + 6 = 12 faces

<span>We can conclude that there are 12 faces in on the four geometric shapes on the holes.
</span>
f. Remember that an edge is a line segment on the boundary of the polygon.
- A sphere has no edges.
- A cone has no edges.
- A rectangular pyramid has 8 edges.
- A rectangular prism has 12 edges.
Total edges: 8 + 20 = 20 edges

Since we have 20 edges in total, we can conclude that your boss will need 20 brackets on the four shapes.

g. Remember that the vertices are the corner points of a polygon.
- A sphere has no vertices.
- A cone has no vertices.
- A rectangular pyramid has 5 vertices.
- A rectangular prism has 8 vertices.
Total vertices: 5 + 8 = 13 vertices

We can conclude that there are 0 vertices for the sphere and the cone; there are 5 vertices for the pyramid, and there are are 8 vertices for the solid (rectangular prism). We can also conclude that your boss will need 13 brackets for the vertices of the four figures.

7 0

3 years ago

The cost of attendance at State College is $19,500 for the first year. Devise a periodic savings plan that will allow you to mak

ValentinkaMS [17]

We are told to use simple interest rate. Formula for this is:
$A=P*(1+r*t)$

Where:
A= total accumulated amount (principal + interest)
P= principal
r= yearly percentage rate
t= number of years

We need to save $19500 for the first year at a college. This is the amount we will have at the account after five years. In our case this is A.
Principal is the amount we need to put into savings to get the total amount needed. In our case this is P.
Yearly percentage rate is the percentage by which our savings increase at the end of a year. In our case this is r.
t is number of years that we are holding our money on the bank account.

To solve this problem we will assume that we are putting same amount each month on the bank account.

We are given:
A=$19500
P=?
r=1.5%
t=5 years

First step is to transform r into decimal number:
$r= \frac{1.5}{100} =0.015$

Now we get back to our formula and we solve it for P:
$A=P*(1+r*t) \\ P= \frac{A}{1+r*t}$
We insert numbers and we get our principal:
$P= \frac{19500}{1+0.015*5} \\ P=18139.53$

We need to put $18139.53 into savings to get required amount after 5 years or 5*12=60months. Assuming that we put same amount each month into savings we need to put
$18139.53 / 60 = 302.33$

This is our solution for this problem. This is closest to the amount we would need to put in real life. In real life we would earn interest onto interest and our monthly amount would be smaller.

3 0

3 years ago