Answer:
x = 17
Step-by-step explanation:
x + x + 8 = 42 because x = boys and x + 8 = girls
2x = 34 because 2x = 42 - 8
x = 17
i hope this helps! you don't need the 2x = 42 - 8 to be an equation ;)
B. 84
The scale factor is 1/12 which means to get back to the actual height, you would multiply 7x12
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
The actual wingspan of the airplane would be 504 which isn't an answer but maybe you just typed A. in incorrectly <span />