Not sure why such an old question is showing up on my feed...
Anyway, let

and

. Then we want to find the exact value of

.
Use the angle difference identity:

and right away we find

. By the Pythagorean theorem, we also find

. (Actually, this could potentially be negative, but let's assume all angles are in the first quadrant for convenience.)
Meanwhile, if

, then (by Pythagorean theorem)

, so

. And from this,

.
So,
Answer:
The total cost is D) $141
Step-by-step explanation:
To solve we can use the equation: 
d= number of days m= number of miles
We know both of these values so we can plug them in and solve.
y= 25(3) + 0.10(660)
y= 75 + 66
y = 141
Answer:
2x<20 (divide both sides by 2, same as you would if an = were between them)
x<10 or B