# Pre-Cal

posted by .

Two airplanes take off from an airport at the same time. One travels on a heading of 45 at 420 mph and the other on a heading of 150 at 400 mph. After two hours, how far apart are the airplanes?

A.650.66 miles
B.1,160 miles
C.1,301 miles

• Pre-Cal -

Use the cosine law, I got 650.66

• Pre-Cal -

Can you tell me how you did it? I got 5 more questions like this one.

• Pre-Cal -

are you not familar with the cosine law?
You must have learned this to be able to do this kind of question.

• Pre-Cal -

Yes I am, but I don't understand it. I don't have a teacher to teach me. I do my work online, and I just need 2nd semester of pre-cal to graduate.

• Pre-Cal -

x^2 = 420^2 + 400^2 - 2(420)(400)cos 105°
do the arithmetic

I got 105° from the difference between 150° and 45°

• Pre-Cal -

thanks

• Pre-Cal -

d1 = 420mi/h[45o] * 2h = 840mi[45o]

d2 = 400mi/h[150o] * 2h = 800mi[150o]

D = 840[45o] - 800[150o]

X = 840*Cos45 - 800*cos150 = 1287 mi
Y = 840*sin45 - 800*sin150 = 194 mi

D = sqrt(1287^2+194^2) = 1301.5 mi

## Similar Questions

Write one or two equations to represent the situation below. Solve the equation(s). Show all your work. Two cars leave town going in opposite directions. The car heading north travels at 55 mph. The car heading south travels at 75 …
2. ### Help w/this one again(Math!!)

Write one or two equations to represent the situation below. Solve the equation(s). Show all your work. Two cars leave town going in opposite directions. The car heading north travels at 55 mph. The car heading south travels at 75 …
3. ### physics

two airplanes leave an airport at the same time. the velocity of the first airplane is 700 m/h at a heading of 52.2degrees . the velocity of the second is 600 m/h at a heading of 97 degrees . how far apart are they after 3.1 h?
4. ### maths

If two planes leave the same airport at 1:00 PM, how many miles apart will they be at 3:00 PM if one travels directly north at 150 mph and the other travels directly west at 200 mph?
5. ### trig

Two airplanes leave a airport at the same time , one going northwest ( bearing 315degrees) at 422 mph and the other going east at 341 mph. How far are the planes after 4 hours ?
6. ### math

two planes take off from an airport at the same time and head in opposite directions at 260 mph and 275 mph respectively. in how many hours will they be 1605 miles apart?
7. ### Pre-Calculus-Trig

Two trains depart simultaneously from the same station. The angle between the two tracks on which they leave is 120 degrees. One train travels at an average speed of 45 mph and the other at 70 mph. How far apart are the trains after …
8. ### physics

Two airplanes leave an airport at the same time. The velocity of the first airplane is 710 m/h at a heading of 27.5 ◦ . The velocity of the second is 650 m/h at a heading of 167◦ . How far apart are they after 3.3 h?
9. ### Math

a plane traveling at 400 mph leaves the philadelphia airport at 1pm heading due east. two hours later a second plane traveling at 600 mph leaves the airport heading in the same direction. at what time does the second plane overtake …
10. ### Physics

Two airplanes leave an airport at the same time. The velocity of the first airplane is 730 m/h at a heading of 44.6 degrees. The velocity of the second is 610 m/h at a heading of 100 degrees. How far apart are they after 2.3 h?

More Similar Questions