Friday

December 19, 2014

December 19, 2014

Posted by **Nada** on Tuesday, July 20, 2010 at 7:55pm.

- Trig-sine, cosine law -
**Reiny**, Tuesday, July 20, 2010 at 8:00pmNow this one is easy to see and draw.

direct application of cosine law,

x^2 = 20^2 + 15^2 - 2(20)(15)cos 25°

= 81.21533

x = 9.01 km

- Trig-sine, cosine law -
**Nada**, Tuesday, July 20, 2010 at 8:05pmUm the answer I was given was 5.7km or 30.5km

So how wud u get these answers?

- Trig-sine, cosine law -
**Reiny**, Tuesday, July 20, 2010 at 9:54pmYup, I made a mistake, I didn't mind my P's and Q's

I now have the fire at F, and PQ=20, FQ=15 and angle QPF=25°

so we have the ambiguous case of the sine law.

let PF = x

first we have to find angle F

sinF/20 = sin25/15

sinF = .5635

angle F = 34.3° , then angle Q = 120.7

or angle F = 145.7°, then angle Q = 9.3°

case 1:

x/sin 9.3 = 15/sin25

x = 5.73

case 2

x/sin120.7 = 15/sin25

x = 30.52

x =

- Trig-sine, cosine law -
**Nada**, Tuesday, July 20, 2010 at 10:03pmThank you so much:)

**Answer this Question**

**Related Questions**

Math - two forest fire stations,P and Q are 20.0 km apart, A ranger at station Q...

math - a fire is sighted from two ranger stations that are 6000 meters apart. ...

analytic geometry - A forest ranger in a 120ft observation tower sees a fire. ...

Trigonometry (Law of Sine) - Fire towers A and B are located 10 miles apart. ...

Trigonometry (Law of Sine) - Fire towers A and B are located 10 miles apart. ...

Trig word problem - A park ranger at point A sights a redwood tree at point B ...

Pre-Calc - Two lookout towers on Mount Abraham and Snow Mountain are 29 miles ...

Math - A forest ranger in a 140-foot observation tower sees a fire moving in a ...

Principles of Math 11 - A ranger in fire tower A spots a fire at a bearingof 295...

5th Grade Math Problem - I posted this a little while ago, but didn't see it. ...