TI-83/84 Calculator trouble for sin, cos, and tan? What am I doing wrong? :(?

Ok so I'm doing physics hw and the book is explaining how to do it in a sample problem and shows this A 305N force is exerted on a sled at an angle of 35*. How much of this force is pulling along the ground and how much is lifting the sled? (So I need to find sides a and b, since I already have c right?) So I... show more Ok so I'm doing physics hw and the book is explaining how to do it in a sample problem and shows this
A 305N force is exerted on a sled at an angle of 35*. How much of this force is pulling along the ground and how much is lifting the sled?
(So I need to find sides a and b, since I already have c right?) So I follow these steps given to me to find a.

c = 305 N
θ = 35*
cos θ = a/c
a = c cos θ
a = (305 N) (cos 35*)
a = 250

So side a equals 250 according to the book, but when I put the exact problem into my calculator
a = (305 N) (cos 35*) I get the answer of -275.6261226
My steps:
First I put cos(35) into the calculator and it says -0.9036922051 then I multiply that to 305.
Obviously its not so obvious how do I put this equation into my calculator and get the correct answer? Or am I supposed to do it another way? Plz help if you can? I'm running out of time to finish this I'm exhausted!
Update: Oh wow that's it! Thanks you guys so much! :)
Would have been great if the teacher mentioned that... :/ But thank you! I got it right just now