Answer:
cos(x-30)=1/2
Step-by-step explanation:
We use the following relationship to obtain cos(x)

From that, we have that cos(x)= sqrt(1-1/4)=sqrt(3) / 4
To obtain the value of cos(x-30), lets remember the following expression:

Therefor, we can use that to obtain our desired function cos(x-30)
cos(x)*cos(30)+sin(x)*sin(30)

=2/4=1/2
Answer:
16 anos
Step-by-step explanation:
Part A
2:7 x 10:x
7 x 10=70 and 2 x x= 2x.
70 divided by 2 is 35, So for 10 the actual is 35 ft.
2:7 x 20:x
7 x 20= 140 and 2 x x=2x.
140 divided by 2 is 70, So for 20 the actual is 70 ft.
Part B
35 x 0.30=10.5
70 x 0.30=21
10.5+21=31.5
$31.5