[Tishax2]

basically who knows 'radian measures' etc ? i dont seem to understand it

can someone just list the simple need to knows please
i know that
l=rtheta

i dont know anything else- thanks

[0range]

LOL what?

[Hasufel]

Arc thenth of part of a circle = r(theta) where r is measured in radians

Area of sector of a circle = (1/2)r^2(theta)

convert degrees to radians: Example: 70 degrees = 70 x (pi/180)

(1 radian is approx 57.3 degrees)

a complete circle is 360 degrees which is: 360 x (pi/180) = 2Pi radians

convert radians to degrees: rads x (180/Pi) - i.e. Pi/2 = (pi/2) x(180/Pi) = 180/2 = 90 degrees

[DeadBullyMafiosi]

C2 is a piece of cake

[Hasufel]

why don`t you help then?...

[Tishax2]

thanks hasufuel
besides area of sector/segmant
and length of arc
what else do i need to know ?

one question gives a small equal triangle with a circle going around it

the radius i 2 and the length along the bottom is 2.4 and it asks to find the leng of the 'circumferance' [disincluding the 2.4]

but you need to find the angle first- how would you find the angle ?

it shows half of that triangle [isosceles] with the H as 2 and the ajacent as 1.2 and it wants the angle :s ?

[Nick_]

The angle in radians is the ratio between the radius:arc length
So if you have a sector (slice of pizza shape), then the arc length/radius= the angle in radians in the center.
As the circumference of a circle is 2*pi*r then the number of radians in 360 degree is 2*pi.
(2*pi*r)/r=2*pi.

From this we can work out that the arc length = angle at center in radians * radius
and area=radius^2*angle at center*0.5

[Tishax2]

okay thanks
also what are all the formulas to do with that section that i need to know ?
whats the formula of a circle and length and diameter and area
and of the arc and sector and segmant and triangle

also wats the difference between length and circumferance
can someone please write the little formulas out for me- the book is confusing
thank you