Problem 9
r+h = 9
SA = 2*pi*r^2 + 2*pi*r*h = 54pi
2*pi*r^2 + 2*pi*r*h = 54pi
2pi*r(r + h) = 54pi
r(r+h) = 27
r(9) = 27
9r = 27
r = 27/9
r = 3
r+h = 9
h = 9-r
h = 9-3
h = 6
Answers: r = 3 and h = 6 are the radius and height respectively.
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Problem 10
d = diameter = 68 mm
r = radius = d/2 = 68/2 = 34 mm
SA = surface area of a sphere
SA = 4*pi*r^2
SA = 4*pi*34^2
SA = 4264pi
Answer: 4264pi square mm
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Problem 11
Plug V = 3000 into the sphere volume formula and isolate r.
V = (4/3)pi*r^3
3000 = (4/3)pi*r^3
(4/3)pi*r^3 = 3000
4pi*r^3 = 3*3000
4pi*r^3 = 9000
r^3 = 9000/(4pi)
r = cube root( 9000/(4pi) )
r = ( 9000/(4pi) )^(1/3)
r = 8.947002 approximately
Now we can determine the surface area of this sphere.
SA = 4pi*r^2
SA = 4*pi*( 8.947002 )^2
SA = 1005.923451
Answer: 1005.923451 square feet approximately
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Problem 12
We'll follow the same idea as problem 11, but in reverse.
SA = 4*pi*r^2
400pi = 4pi*r^2
r^2 = (400pi)/(4pi)
r^2 = 100
r = sqrt(100)
r = 10
Luckily we get a nice whole number for the radius r. Use it to find the volume.
V = (4/3)*pi*r^3
V = (4/3)*pi*10^3
V = (4000/3)pi
Answer: (4000/3)pi cubic inches exactly
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Problem 13
The diagram is missing. I don't have enough info to be able to answer.
Answer:
The approximate volume of the tube is 1,005 cm³
Step-by-step explanation:
To find the volume of the tube, we will follow the steps below:
First, write the formula for calculating the volume of a cylinder
volume of a cylinder = πr²h
where r is the radius and h is the height of the cylindrical cardboard tube
from the question given, height is equal to 20 centimeters and diameter = 8 centimeters but diameter = 2r, this implies that r = d/2 hence radius r =8/2 = 4 centimeters
π is a constant and is ≈ 3.14
we can now proceed to insert the values into the formula
volume of a cylinder = πr²h
≈ 3.14 × 4²× 20
=3.14 × 16× 20
≈1,005 cm³ to the nearest whole cubic centimeter.
The approximate volume of the tube is 1,005 cm³
1. A square is a figure with four sides that have the same lenght. So, to solve this problem and calculate the area of the square, you must apply the following formula:
A=(s)(s)
A=s²
"A" is the area of the square.
"s" is the lenght of the side of the square.
2. So, the lenght of the side given in the problem is 5^2/5 inches (s=5^2/5 inches). Therefore, you only have to substitute this value into the formula A=s².
3. Then, you obtain:
A=s²
A=(5^2/5 inches)²
A=5^4/5 inches²
What is the area of the square?
The answer is: A. 5^4/5 square inches.
Answer:
90 points
Step-by-step explanation:
90 x .80 = 72 points
Answer:
Step-by-step explanation:
3x-20=x+40
2x=60
x=30, then
y+x+40=180, knowing x=30
y+30+40=180
y+70=180
y=110