Homework Help: Math

Posted by Crystal on Saturday, November 24, 2012 at 8:18pm.

3) From two tracking stations A and B, 350 km apart, a UFO is sighted at C above AB making angle CAB = 32 degrees and angle CBA = 54 degrees. Find the height of the UFO.

The answer is 150 km, please explain to me how

4) from a boat on the water, the angle of elevation at the top of the cliff is 31 degrees. From a point 300 m closer, the angle of elevation is 33 degrees. Find the height of the cliff.

Answer is 2411 m

5) from the top of a cliff 185 m high, the angles of depression of two channel buoys in the same line of sight on the water are 13 degrees and 15 degrees. How far apart are the buoys?

The answer is 111 m.

I'm having a lot of trouble figuring out these questions. When I try to do them, I feel like there's missing information. Or I'm misinterpreting the questions. Please help

Math - Damon, Saturday, November 24, 2012 at 8:53pm
SKETCH the problem
draw altitude h down from C to line AB at D
call AD x
then DB is 350 -x
Now look at right triangle ACD
tan 32 = h/x = .625
so
x = h/.625 = 1.6 h
Now triangle BCD
tan 54 = h/(350-x)
1.38 = h/(350 -1.6 h)
482 - 2.20 h = h
3.2 h = 482
h = 151 meters
Math - Damon, Saturday, November 24, 2012 at 8:54pm
If you follow that you can do the other two.
Math - Damon, Saturday, November 24, 2012 at 9:00pm
Sorry, kilometers, not meters
Look down at the bottom of the page for related problems solved. Look particularly at this one:
http://www.jiskha.com/display.cgi?id=1279657357
Math - Crystal, Saturday, November 24, 2012 at 10:40pm
How did you get x = h/.625 = 1.6 h ? How did you arrive at 1.6?
Math - Damon, Saturday, November 24, 2012 at 10:58pm
1/.625 = 1.6
Math - Damon, Saturday, November 24, 2012 at 11:13pm
tan 32 = h/x
so
x tan 32 = h
so
x = h/tan 32
so
x = h/.625
but 1/.625 = 1.6
so
x = 1.6 h
Math - Crystal, Saturday, November 24, 2012 at 11:43pm
Thanks! I don't know how I missed that.
Math - Crystal, Sunday, November 25, 2012 at 12:10am
okay so I think I'm still kind of hopeless... my solution to the second question is way off, but here's what I did:

right triangle ABC. (facing like this: >) so that AB is the hypotenuse, and I labelled AC as h for the height of the cliff. I drew a dotted line from point A to about the middle of line BC and called that point D.

Made angle ABD 31 degrees, angle ADC 33 degrees, line BD x+300, line DC x.

for triangle ADC:

tan33=h/x
x=h/tan33
x=h/0.65

for triangle ABC:

tan 31=h/x+300+x
0.6 = h all over h/0.65 +300 + h/0.65
0.6 =h x (1.3/2h) + 300
0.6 - 300 = 1.3/h
-299.4 = 1.3/h
h = 1.3/299.4
h = 0.004 .....

Yeah, I guess I really don't get this... *sigh*
Math - Damon, Sunday, November 25, 2012 at 6:38am
It was midnight. I went to bed.

Made angle ABD 31 degrees, angle ADC 33 degrees, line BD x+300, line DC x.

for triangle ADC:

tan33=h/x
x=h/tan33
x=h/0.65

for triangle ABC:
tan 31 = h/(x+300)
.6 = h/(x+300)
.6 x + 180 = h
.6(h/.65) + 180 = h
.92 h + 180 = h
180 = .08 h
h = 2250
need to carry more significant figures to get a more accurate answer
Math - Crystal, Sunday, November 25, 2012 at 9:05am
Completely understandable, thank you so much for checking back though!

Answer this Question

Related Questions

Trig - From two different tracking stations, a weather balloon is spotted from ...
Grade 11 math - A rocket carrying a weather satellite is launched. As it moves ...
trig pls.. help me - A rocket carrying a weather satellite is launched. As it ...
math - a fire is sighted from two ranger stations that are 6000 meters apart. ...
Algebra 2 - A UFO is first sighted at point A due east from an observer at an ...
Math - Hi, I am doing a practice exam, and I came across this problem and I am ...
Math - A rocket tracking station has two telescopes A and B placed 1.9 miles ...
Math - To chart the movement of a polar bear, scientists attached a radio ...
PHYSICS help!!!!!! - A commuter train travels between two downtown stations. ...
Math - two forest fire stations,P and Q are 20.0 km apart, A ranger at station Q...

For Further Reading

First Name:
School Subject:
Answer: