Trig formula problem

[prostreet]

Please help
I have been trying for days to solve a formula in Excel.
I am attempting to find the length of a cord, knowing the radius & the angle.
The formula is 2 * r * sin(theta/2)
r = 2, theta = 89
When using a scientific calculator, I get 2.8036, the exact dimension as I get in Autocad.
When I try to do this in Excel using 2 * 2 * ( sin 89/2)) I get 1.980
Can anyone help me achieve the correct answer?
Any help would be appreciated.
Thank you.
Jerome

 

[skywriter]

I think in Excel you don't use cosine, sine, tangent with degrees, you have to change the angle to radians before using those functions.

It's been a while since I converted degrees to radians, but I'm sure it's easy enough to find with google.

I remember that there's 2*PI radians in a circle which is 360 degrees, but the straight conversion from degrees to radians escapes me, maybe degrees * pi/180?

 

[prostreet]

I tried pi/180 & 180/pi and it doesn't work. Thanks for the input.

 

[skywriter]

=2*2*SIN((89*(PI()/180)/2))
Gives me the answer you came up with.
2.803637

 

[skywriter]

Here's another one that easily converts the angle to radians.
=2*2*SIN(RADIANS(89/2))
Same answer as the other one.
2.803637