43.71, 43.6, 41.92 greatest to least
Answer:
17
but it can be 18 too
cuz the q doesn't tell us that the value of x has to be a prime no.
Step-by-step explanation:
2+3+5+7+11+13+17=58
We'll use the following properties of sine and cosine to prove this:



Then it's just a matter of filling it in...
sin20sin40 * sin60sin80 = 1/2(cos20 - cos60) * 1/2 (cos20 - cos140) =
1/8( cos40 + 1 - cos160 - cos120 - cos40 - cos80 + cos80 + cos200) =
1/8(1 - cos160 - cos120 + cos200) =
1/8(1 - cos160 - cos120 + cos160) =
1/8(1 - cos120 ) = 1/8( 1 + 1/2 ) = 3/16