circumference | MathCelebrity Forum

# circumference

1. ### 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 = 2.5 or 2&1/2
2. ### 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: C = 2πr or πd
3. ### 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...
4. ### 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)
5. ### If the circumference of a circular rug is 16π feet, then what is the area of the rug in terms of pi

If the circumference of a circular rug is 16π feet, then what is the area of the rug in terms of pi C = 2pir, so we have: C = 16π 16π = 2πr Divide each side by 2π: r = 16π/2π r = 8 Now, the area of a circle A is denoted below: A = πr^2 Given r = 8 from above, we have: A = π(8)^2 A = 64π
6. ### A bicycle wheel is one meter around. If the spikes are 4 centimeters apart, how many spokes are on t

A bicycle wheel is one meter around. If the spikes are 4 centimeters apart, how many spokes are on the wheel altogether? 1 meter = 100 cm per our conversions calculator 100 cm for the whole circle / 4 cm for each spike = 25 spikes
7. ### 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...
8. ### 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 C ~ 150.8