Which of the following could be used to find the height of the flagpole shown?

Question

anonymous · Answer

x = 5 cos 40°
       x = 5 cos 50°
       x = 5 sin 40°
       x = 5 tan 50°

ranga · Answer

Are you sure you typed all the answer choices correctly?

Let 'x' be the height of the flagpole.
sin(50) = opposite / hypotenuse = x / 5
x = 5sin(50).

anonymous · Answer

thank you .

ranga · Answer

Oh, BTW, sin(50) is same as cos(40).   So 5sin(50) = 5cos(40).  So (A).

anonymous · Answer

oh ohkay i was just about to ask

ranga · Answer

sin(x) = cos(90-x).
sin(50) = cos(90-50) = cos(40).

This is true of ALL "co" trig functions: sine and "co"sine, tan and "co"tan or cot, sec and "co"sec or csc.  

tan(x) = cot(90-x)   and  cot(x) = tan(90-x), etc..