Trig problem (Diagram included)

[supernova1203]

Homework Statement

A satellite dish that is 5m high sits atop a building, from a point at the base of building, the angles of elevation of the bottom and the top of the satellite dish are 39.1 degrees and 44.7 degrees. Determine the height of the building to one decimal place.

Homework Equations

Sine law: a/SinA = b/SinB=c/SinB

Cosine law: c^2=a^2+b^2-2abCosC

Pythagorean theorem: a^2+b^2= c^2

The Attempt at a Solution

We are originally just given the 5m and the 2 angles 44.3 degrees and 39.1 degrees
rest is included in diagram which i obtained either using one of the 3 laws or the supposition that a triangle has in total a 180 degrees of angles.

triangle = 3 angles which total in 180.

 

[eumyang]

The side labeled "5.09 m" can't be right. That is the longest side of the top triangle, so it has to be greater than 36.35 m. After you fix that, use the sine ratio for either right triangle to solve for h.

 

[supernova1203]

The side labeled "5.09 m" can't be right. That is the longest side of the top triangle, so it has to be greater than 36.35 m. After you fix that, use the sine ratio for either right triangle to solve for h.

your right, first off in my calculations i used tan, instead of sin which would make sense, i re did the calculations and it comes out to be 51.5 m instead of 5.09m.

Also the course teaches us how to use the sine ration, but it ends up being h+5 which is hard for me to solve @_@

 

[eumyang]

your right, first off in my calculations i used tan, instead of sin which would make sense, i re did the calculations and it comes out to be 51.5 m instead of 5.09m.

Also the course teaches us how to use the sine ration, but it ends up being h+5 which is hard for me to solve @_@

I'm not getting 51.5m either.

Also, it's not hard using the sine ratio. Using the hypotenuse of the smaller right triangle (which is about 36.42, not 36.35), you don't even need to worry about the h+5:
$$\sin 39.1^{\circ} = \frac{h}{36.42}$$

EDIT: Also, θ1 + θ2 in the diagram is incorrectly labeled as 44.3°. It should be 44.7°