9 results

circumference - the perimeter of a circle or ellips

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 tractor tire has a radius of 24 inches. If the tire rotates one time around, about how many inches

A tractor tire has a radius of 24 inches. If the tire rotates one time around, about how many inches of ground will it cover? Use 3.14 for pi.
A tractor tire is a circle. We want the circumference, which is the distance around the tire.
C = 2pir
C = 2(3.1415)24
[B]C ~ 150.8[/B]

Circles

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

Hemisphere

Free Hemisphere Calculator - Calculates the base circumference, volume, curved surface area, base surface area, total surface area of a hemisphere with radius r

If the circumference of a circular rug is 16? feet, then what is the area of the rug in terms of pi

If the circumference of a circular rug is 16? feet, then what is the area of the rug in terms of pi
C = 2pir, so we have:
C = 16?
16? = 2?r
Divide each side by 2?:
r = 16?/2?
r = 8
Now, the area of a circle A is denoted below:
A = ?r^2
Given r = 8 from above, we have:
A = ?(8)^2
A = [B]64?[/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)

Laura found a roll of fencing in her garage. She couldn't decide whether to fence in a square garden

Laura found a roll of fencing in her garage. She couldn't decide whether to fence in a square garden or a round garden with the fencing.
Laura did some calculations and found that a circular garden would give her 1380 more square feet than a square garden. How many feet of fencing were in the roll that Laura found? (Round to the nearest foot.)
Feet of fencing = n
Perimeter of square garden = n
Each side of square = n/4
Square garden's area = (n/4)^2 = n^2/16
Area of circle garden with circumference = n is:
Circumference = pi * d
n = pi * d
Divide body tissues by pi:
d = n/pi
Radius = n/2pi
Area = pi * n/2pi * n/2pi
Area = pin^2/4pi^2
Reduce by canceling pi:
n^2/4pi
n^2/4 * 3.14
n^2/12.56
The problem says that the difference between the square's area and the circle's area is equal to 1380 square feet.
Area of Circle - Area of Square = 1380
n^2/12.56 - n^2/16 = 1380
Common denominator = 200.96
(16n^2 - 12.56n^2)/200.96 = 1380
3.44n^2/200.96 = 1380
Cross multiply:
3.44n^2 = 277,324.8
n^2 = 80,617.7
n = 283.9
Nearest foot = [B]284[/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]

When the circumference of a circle is increased from 10 pi inches to 15 pi inches, by how many inche

When the circumference of a circle is increased from 10 pi inches to 15 pi inches, by how many inches is the radius increased?
C = 2pir
Smaller circle:
2pir = 10pi
Divide each side by 2pi:
r = 5
Larger circle:
2pir = 15pi
Divide each side by 2pi:
r = 7.5
Difference = 7.5 - 5 = [B]2.5 or 2&1/2
[MEDIA=youtube]HvMNNffcv78[/MEDIA][/B]