# Trig. Questions

• Mar 6th 2011, 02:18 PM
roinujo1
Trig. Questions
I need some help on these two problems. I couldnt undestand how to draw a picture for it, but bare with me.

You are watching a fireworks display where you are standing 290 ft behind the launch pad. The launch tubes are aimed away from you at an angle of 65 degrees with the ground. The angle of elevation for you to see the fireworks is 40 degrees.

1.To the nearest ft., what is the horizontal distance from the launch pad to the ignition point of the fireworks?

2. To the nearest ft, what is the height of the fireworks when they ignite?
• Mar 6th 2011, 02:50 PM
Wilmer
Code:

```                  A(ignite) B(you)      C(pad) D```
BC = 290 ft
angleACD = 65 degrees
angleABC = 40 degrees
AD = vertical distance, CD = horizontal distance

All yours...
• Mar 6th 2011, 02:53 PM
roinujo1
Ok but how do i find the horizontal distance. When i did it i got 103 ft.
• Mar 6th 2011, 03:46 PM
Wilmer
You're not showing any work...so I don't know what you can do!

Anyway, angle ACB = 180 - 65 = 115; angle BAC = 180 - 40 - 115 = 25.
So you have all angles of triangle ABC plus BC = 290.
Calculate length of AC using Law of Sines.
Then proceed to right triangle ACD.
If you can't handle that, you need classroom help.
• Mar 6th 2011, 03:50 PM
roinujo1
Quote:

Originally Posted by Wilmer
You're not showing any work...so I don't know what you can do!

Anyway, angle ACB = 180 - 65 = 115; angle BAC = 180 - 40 - 115 = 25.
So you have all angles of triangle ABC plus BC = 290.
Calculate length of AC using Law of Sines.
Then proceed to right triangle ACD.
If you can't handle that, you need classroom help.

I get all that but how can you use the sines ratio. its not a right triangle
• Mar 6th 2011, 04:53 PM
Wilmer
Look up the Law of Sines!
AC / SIN(40) = 290 / SIN(25)
• Mar 6th 2011, 05:11 PM
roinujo1
Quote:

Originally Posted by Wilmer
Look up the Law of Sines!
AC / SIN(40) = 290 / SIN(25)

Dont think we got that far in our lesson. for AC I got 441
• Mar 6th 2011, 07:07 PM
Wilmer
Keerect!
Now with right triangle: vertical = 400, horizontal = 186 (both rounded)
Got that?