Question

Whats the formula for finding the distance between two concentric circles?

Answer 1

radius of the larger minus the radius of the smaller.

Answer 2

What about archs?

Answer 3

Here's an example question: http://answers.yahoo.com/question/index?qid=20081014134103AA4Uff8

"What about archs?"

Did you mean arches or arcs of circles? Either way, I'm not sure what you're asking for...

Answer 4

Jason designed an arch made of wrought iron for the top of a mall entrance. The 11 segments between the two concentric circles are each 1.25 m long. Find the total length of wrought iron used to make the structure. Round the answer to the nearest meter.

Im trying to figure out what formula to use for this

Answer 5

Is there a diagram? "11 segments between the two concentric circles are each 1.25 m long" ???

Answer 6

1.25m is therefore the difference between the radii. The diameter of the outer arch is... 15m??

Answer 7

We just need to find the length of the two semicircles. The first one is easy:

diameter is 15m (????) so radius is 7.5m. Can you find half the circumference of a circle?

Inner arch has a radius 7.5-1.25m. Then you need to find half the circumference of that circle.

Answer 8

C=2(pie)r. so 41.7?

Answer 9

6.25.. so then C=2(pie)r and thats 39.25 for the other circle.. right?

Answer 10

I think you meant 47.1m for the first circle, but yes. But... remember that we don't want the whole circumference of the circles...

Answer 11

So half of both of those

Answer 12

Correct. But that's not all you need...

"The 11 segments between the two concentric circles are each 1.25 m long. Find the total length of wrought iron used to make the structure. Round the answer to the nearest meter."

Answer 13

half of those is 23.55 and 19.625. what do I do for the next part?

Answer 14

"Find the total length of wrought iron used"

There's the two semicircles, as well as... "The 11 segments between the two concentric circles are each 1.25 m long. "

Answer 15

forgive me, i dont get it haha. Is there a formula or..

Answer 16

How would you find the total length of iron used? You already know the lengths of iron used in the two semicircles... the question tells you that there's 11 pieces that are 1.25m.

Answer 17

multiply 11 and 1.25?

Answer 18

Yes

Answer 19

so 13.75!!

Answer 20

But you still need the TOTAL length. The two semicircles are 23.55m and 19.625m, then there's the 13.75m from the other 11 pieces.

Answer 21

ahhh 56.925m is the total

Answer 22

thank you so much!