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Anniep418

Guest

Circles: Circumference and Arc Length

Hi, I need some help on these problems.

What is the radius if:
16. n=30 L=1/3xy(pi) I got C. The other ones I need help explaining.

A6xy
B8xy
C2xy
D10xy
E 3xy
F 14xy

17. n=40 L=8/9(t)(pi)

A20t
B5t
C9t
D18t
E 12t
F 4t

18. n=15 L=(21/36)pi

A7
B21
C28
D62
E 56
F 14

19. n=5 L=1/2pi

A24
B30
C45
D18
E 66
F 39

20. n=18 L=6(y)pi

A30y
B45y
C120y
D90y
E 15y
F 60y

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Circles: Circumference and Arc Length

Hi;

What are n and L?

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In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Circles: Circumference and Arc Length

Length as in arc length?

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

anniep418

Member

Registered: 2016-07-28

Posts: 11

Re: Circles: Circumference and Arc Length

Yes! Sorry I should have provided more info.

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Circles: Circumference and Arc Length

Okay, I will start on them as soon as I finish with another problem.

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

thickhead

Member

Registered: 2016-04-16

Posts: 1,086

Re: Circles: Circumference and Arc Length

set

in each case.Your answer for (16) is correct. Carry out others in the same way.

Last edited by thickhead (2016-07-28 05:07:40)

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{1}Vasudhaiva Kutumakam.{The whole Universe is a family.}
(2)Yatra naaryasthu poojyanthe Ramanthe tatra Devataha
{Gods rejoice at those places where ladies are respected.}

anniep418

Member

Registered: 2016-07-28

Posts: 11

Re: Circles: Circumference and Arc Length

Thank you so much for that new formula! The formula they gave me was so complicated, which is one of my main problems in math. Teachers always give us the most complicated formulas when there are easier ways to do it!

So for 17 I got F.

18 is A.

19 is D.

20 is F.

bobbym

bumpkin

From: Bumpkinland

Registered: 2009-04-12

Posts: 109,606

Re: Circles: Circumference and Arc Length

Hi;

17 is correct.

18 is correct.

19 is correct.

20 is correct.

Very good!

---

In mathematics, you don't understand things. You just get used to them.
If it ain't broke, fix it until it is.
Always satisfy the Prime Directive of getting the right answer above all else.

thickhead

Member

Registered: 2016-04-16

Posts: 1,086

Re: Circles: Circumference and Arc Length

hi Anniep418,
It is a bad habit to depend on formulae. You are taught that arc length is proportional to the angle inscribed. Since the full circumference corresponds to 360 degrees you have to develop the formula yourself.
arc length /(2 pi R)=angle/360.

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{1}Vasudhaiva Kutumakam.{The whole Universe is a family.}
(2)Yatra naaryasthu poojyanthe Ramanthe tatra Devataha
{Gods rejoice at those places where ladies are respected.}