diameter - distance from two endpoints of a circle through the center

Formula: d = 2r

A gardener wants to fence a circular garden of diameter 21cm. Find the length of the rope he needs t

A gardener wants to fence a circular garden of diameter 21cm. Find the length of the rope he needs to purchase, if he makes 2round of fence Also find the cost of the rope, if it costs Rs4 per meter (take pie as 22/7)
Circumference of a circle = Pi(d).
Given Pi = 22/7 for this problem, we have:
C = 22/7(21)
C = 22*3
[B]C = 66[/B]

A lead pipe 20 ft long is 3/8 inch thick and has an inner diameter of 3 inches. Find the volume of l

A lead pipe 20 ft long is 3/8 inch thick and has an inner diameter of 3 inches. Find the volume of lead in it.
A lead pipe is a cylinder. We want the volume of a cylinder.
Convert 20ft to inches:
20ft = 12(20) = 240 inches
Find the inner radius:
1/2 * inner diameter
1/2 * 3 = 3/2
Now add the thickness for the total radius
3/2 + 3/8 = 12/8 + 3/8 = 15/8
Find volume of the lead where volume = pi r^2 h
Lead vol (V) = Overall volume - inner volume
Lead Vol = pi(15/8)^2(240) - pi(3/2)^2(240)
Lead Vol = 240pi(225/64 - 9/4)
9/4 = 144/64
Lead Vol = 240pi(225/64 - 144/64)
Lead Vol = 240pi(81/64)
[B]Lead Vol = 303.75pi[/B]

A mug has 3 inch diameter and is 3.5 inches tall how much water can it hold

A mug has 3 inch diameter and is 3.5 inches tall how much water can it hold
A mug is a cylinder. If the diameter is 3, then the radius is 3/2 = 1.5.
Using our cylinder volume calculator, we get:
[B]V = 7.875pi or 24.74 cubic inches[/B]

A penny has a diameter of 19 millimeters. What is the radius of the penny.

A penny has a diameter of 19 millimeters. What is the radius of the penny.
D = 2r
To solve for r, we divide each side by 2:
r = D/2
Plugging in D = 19, we get:
r = [B]19/2 or 9.5[/B]

A spherical water tank holds 11,500ft^3 of water. What is the diameter?

A spherical water tank holds 11,500ft^3 of water. What is the diameter?
The tank holding amount is volume. And the volume of a sphere is:
V = (4pir^3)/3
We know that radius is 1/2 of diameter:
r =d/2
So we rewrite our volume function:
V = 4/3(pi(d/2)^3)
We're given V = 11,500 so we have:
4/3(pi(d/2)^3) = 11500
Multiply each side by 3/4
4/3(3/4)(pi(d/2)^3) = 11,500*3/4
Simplify:
pi(d/2)^3 = 8625
Since pi = 3.1415926359, we divide each side by pi:
(d/2)^3 = 8625/3.1415926359
(d/2)^3 = 2745.42
Take the cube root of each side:
d/2 = 14.0224
Multiply through by 2:
[B]d = 28.005[/B]

Circle Equation

Free Circle Equation Calculator - This calculates the standard equation of a circle and general equation of a circle from the following given items:

* A center (h,k) and a radius r

* A diameter A(a_{1},a_{2}) and B(b_{1},b_{2})

This also allows you to enter a standard or general form equation so that the center (h,k) and radius r can be determined.

* A center (h,k) and a radius r

* A diameter A(a

This also allows you to enter a standard or general form equation so that the center (h,k) and radius r can be determined.

Circles

Free Circles Calculator - Calculates and solves for Radius, Diameter, Circumference, and Area of a Circle.

Cylinders

Free Cylinders Calculator - Calculates and solves for Radius, Diameter, Volume (Capacity), Lateral Area, and Surface Area of a Cylinder.

Fantasia decided to paint her circular room which had a diameter of 25 feet. She started painting in

Fantasia decided to paint her circular room which had a diameter of 25 feet. She started painting in the center and when she had painted a circle with a 5-foot diameter, she used one quart of paint. How many more quarts of paint must Fantasia buy to finish her room?
The area formula for a circle is:
Area = pir^2
Area of full room
Radius = D/2
Radius = 25/2
Radius = 12.5
Area = 3.1415 * 12.5 * 12.5
Area = 490.625
Area of 5-foot diameter circle
Radius = D/2
Radius = 5/2
Radius = 2.5
Area = 3.1415 * 2.5 * 2.5
Area = 19.625
So 1 quart of paint covers 19.625 square feet
Area of unpainted room = Area of Room - Area of 5-foot diameter circle
Area of unpainted room = 490.625 - 19.625
Area of unpainted room = 471
Calculate quarts of paint needed:
Quarts of paint needed = Area of unpainted Room / square feet per quart of paint
Quarts of paint needed = 471/19.625
Quarts of paint needed = [B]24 quarts[/B]

if my diameter is 19 inches, what is my radius?

if my diameter is 19 inches, what is my radius?
Radius = Diameter/2
Radius = [B]19/2[/B]

If the diameter of a circle is n, what is the circumference?

If the diameter of a circle is n, what is the circumference?
Diameter of a circle = pi(d)
Given d = n, we have:
Diameter = pi(n)

Keith is cutting two circular table tops out of a piece of plywood. the plywood is 4 feet by 8 feet

Keith is cutting two circular table tops out of a piece of plywood. the plywood is 4 feet by 8 feet and each table top has a diameter of 4 feet. If the price of a piece of plywood is $40, what is the value of the plywood that is wasted after the table tops are cut?
Area of the plywood = 4 * 8 = 32 square feet
[U]Calculate area of 1 round top[/U]
Diameter = 2
Radius = Diameter/2 = 4/2 = 2
Area of each round top = pir^2
Area of each round top = 3.14 * 2 * 2
Area of each round top = 12.56 square feet
[U]Calculate area of 2 round tops[/U]
Area of 2 round tops = 12.56 + 12.56
Area of 2 round tops = 25.12 sq feet
[U]Calculate wasted area:[/U]
Wasted area = area of the plywood - area of 2 round tops
Wasted area = 32 - 25.12
Wasted area = 6.88 sq feet
[U]Calculate cost per square foot of plywood:[/U]
Cost per sq foot of plywood = Price per plywood / area of the plywood
Cost per sq foot of plywood = 40/32
Cost per sq foot of plywood = $1.25
[U]Calculate the value of the plywood:[/U]
Value of the plywood = Wasted Area sq foot * Cost per sq foot of plywood
Value of the plywood = 6.88 * 1.25
Value of the plywood = [B]$8.60[/B]

Marco orders a large pizza, with a diameter of 14 inches. It is cut into 8 congruent pieces. what is

Marco orders a large pizza, with a diameter of 14 inches. It is cut into 8 congruent pieces. what is the area of one piece?
A pizza is a circle. If the diameter of the pizza is 14 inches, the radius is 14/2 = 7 inches.
Area of a circle is pi(r^2). With r = 7, we have:
A =7^2(pi)
A = 49pi
Area of a slice of pizza is the area of the full pizza divided by 8
A(Slice) = [B]49pi/8[/B]

Please help me!! I don't understand!

I don't understand this word problem: If each of these shapes in Figure 1 were separated and filled with water, could the sphere that contains the cube hold all of the water? [I]Assume in the second image the corners of the cube touch the sphere so the diagonal from one corner of the cube to the opposite diagonal corner is the diameter of the sphere. [IMG]https://classroom.ucscout.org/courses/1170/files/191225/preview?verifier=mT7v59BhdVHalyprWq0KmBEItbf4CPWFqOgwoEa8[/IMG][IMG]https://classroom.ucscout.org/courses/1170/files/191494/preview?verifier=nsLscsxToebAVXTSYsoMr7rwIl536LrCJSDGPaHp[/IMG][/I]
Could you guys help me please?

The button on Alice's shirt has a diameter of 8 millimeters. What is the button's radius?

The button on Alice's shirt has a diameter of 8 millimeters. What is the button's radius?
Radius = Diameter / 2
Radius = 8/2
Radius = [B]4[/B]

The moon's diameter is 2,159 miles. What is the surface area of the moon? Round to the nearest mile.

The moon's diameter is 2,159 miles. What is the surface area of the moon? Round to the nearest mile.
The moon is a sphere. So our Surface Area formula is:
S =4pir^2
If diameter is 2,159, then radius is 2,159/2 = 1079.5. Plug this into the Surface Area of a sphere formula:
S = 4 * pi * 1079.5^2
S = 4 * pi *1165320.25
S = 4661281 pi
S = [B]14,643,846.15 square miles[/B]

Three tennis balls each have a radius of 2 inches. They are put into a 12 inch high cylinder with a

Three tennis balls each have a radius of 2 inches. They are put into a 12 inch high cylinder with a 4 inch diameter. What is the volume of the space remaining in the cylinder?
Volume of each ball is 4/3 ?r^3
V = 4/3 * 3.1415 * 2^3
V = 1.33 * 3.1415 * 8 = 33.41 cubic inches
The volume of 3 balls is:
V = 3(33.41)
V = 100.23
Volume of the cylinder is area of circle times height:
V = 3.14 * 2 * 2 * 1 = 150.72
Volume of remaining space is:
V = Volume of cylinder - Volume of 3 balls
V = 150.72 - 100.23
V = [B]50.49[/B]

What is the formula for the circumference of a circle?

What is the formula for the circumference of a circle?
Given radius r and diameter d, the circumference C is:
[B]C = 2?r or ?d[/B]