Find the radius from a chord

[JohnS]

[QUOTE=amanda dubuisson]

Originally Posted by amanda

I am not exactly sure what you mean.

The chord meaures the curve of a sector of a circle? so what can u explain to me like in a question for this Circle A has a radius of 3 m. What is the length of the longest chord in circle A? can you help me on that and to show me how you did it.

The chord is the straight line across the end points of the sector. The longest possible chord is a diameter (twice radius).

The formula was very helpful to me. It help me calculate a very large radius on a small part.

what is /2m if m = 20 in your equation

[JohnS]

Originally Posted by Unregistered

what is /2m if m = 20 in your equation

Divide by 40. Perhaps it would be clearer as /(2*m)

I know the radius of a circle and the angle formating at the center by the cord,How can I find the lenght of the cord?

Exp.-If radius=10mtrs. and the angle is 120 degree then the lenght of the cord is?

[JohnS]

Originally Posted by Unregistered

I know the radius of a circle and the angle formating at the center by the cord,How can I find the lenght of the cord?

Exp.-If radius=10mtrs. and the angle is 120 degree then the lenght of the cord is?

If the angle is theta, the chord is
2*r*sin(theta/2) = 2*10*sin(60°) = 17.32 m

By having only two measurements, first the length of the chord and the height of the curve, what is the formula for finding the radius of the circle

[JohnS]

Originally Posted by Nisar1238

By having only two measurements, first the length of the chord and the height of the curve, what is the formula for finding the radius of the circle

see posts #2 and #4 for diagram and formula.

I have the radius and the length of the arc segment how do
I find the length of the chord

[JohnS]

Originally Posted by 6178

I have the radius and the length of the arc segment how do
I find the length of the chord

The central angle, theta, is s/r radians or (s/r)*(180/pi) degrees

The chord is 2*r*sin(theta/2)

The height is r*(1 - cos(theta/2))