PreCalculus
posted by Shreya .
Trigonometric Functions, Radian Measure
∏ < will be using this for pi
Using exact values, convert to radians ( hint use fraction of ∏)
90° = 90°*∏/180° = 1∏/2
^^would it be right to also call it 2∏ radians?
Determine the angle at the centre of the circle, radius 6cm, for each arc length.Express each angle in radians and then in degrees.
3cm
a = rθ
3 = 6θ
1/2 = θ
1/2*180°/∏
=28.6°
^One of my friends got a totally different answer, and she got
θ = 2 rad
2*180/∏ = 114.59
^Ive no idea how she got that :S

PreCalculus 
Steve
It is obvious she is wrong.
the whole circumference of a 6cm circle is 12pi or about 36 cm
3cm is about 1/12 of the whole, or 1/12 of 360° = 30°
she obviously confused the formula.
ALWAYS do a general sanity check on your answers. Just because you get a value doesn't mean that it's correct. 
PreCalculus 
Shreya
Thanks so much :)
Respond to this Question
Similar Questions

CALCULUS
If cos(t)=–7/9, find the values of the following trigonometric functions. Note: Give exact answers, do not use decimal numbers. The answer should be a fraction or an arithmetic expression. a) cos (2t) b) sin (2t) c) cos(1/2) d) sin … 
Trig
Rewrite 25 degrees in radian form. 25 =25(pi radians/180) =25pi/180 radians =5pi/36 
MathTrig
1. Create an algebraic expression for sin(arccosxarcsin3x) 2. The cosx=4/5, x lies in quadrant 4. Find sin x/2 3.Determine all solutions in (0,2pie) for sin4xsin^2x=3, cot^2v(31)cotx=v(3), cos^2x=cosx, and tan^2x6tanx+4=0 4. Solve; … 
calculus
Verify the identity: arctanx + arctan(1/x)=∏/2 using calculus theory. (Hint: Differentiate the left hand side of the identity) 
calculus
evaluate the integral I= ∫(0,∏/4) ((53e^(tanx))/(cos^(2)x))dx 
MAths
Let r1,r2,r3 be the roots of polynomial P(x)=x^3+3x+1. Evaluate the product 3 ∏ (r^2+r +1) k k k=1 
Statistics
A national opinion poll found that 44% of all American adults agree that parents should be given vouchers good for education at any public or private school of their choice. Suppose that in fact the population proportion who feel this … 
Calculus
Determine the exact values of the six trigonometric functions of the angle.(5,2) 
Maths
Tan[2*tan⁻¹⅕∏/4] 
math
There is a diagram of a running track. The track is made up of two straights and two semicircles. The radius of each semicircle is 35 meters. The length of the outer perimeter of the entire running track is 400 meters. Find the length …