# [SOLVED] Few beg. Trig Probs Angles

• June 26th 2009, 07:31 PM
KevinVM20
[SOLVED] Few beg. Trig Probs Angles
So when you have 90-x in a right triangle that you are trying to solve cos sin and tang etc.. those questions, how do you include angle degrees into your calculations.. For instance,

l there is a h(3) line
4 l i just can't
l draw online
l_____________x
5

I know how to simply find these functions by dividing one another but I get confused when it comes to including angles.

I also have a question regarding "clinometer" use.

Well, we can use such an instrument (called a “clinometer”) to measure the angle A. Then we know that the angle between the ground and the building is a right angle, so we know the measure of 3 angles, because they all add up to 180°. Now all we have to do is find a similar triangle anywhere. Then we can measure the ratio of the sides that correspond to the height and the ground length, and then we can multiply by the actual ground length to get the height.

So once you have the three angles, how do you find the measurement on the structure you are trying to identify. I am given a question like this:

Given the angle you are given to the top of the building, calculate the height given distance?

I am unsure how to find the height of the building could someone help?

Here is a sample prob I am given,

Angle 71 Distance 20 Meters

Top

L
l Angle
; in
l box
l
_____________________________71
20
Any potential help appreciated.
• June 26th 2009, 07:49 PM
VonNemo19
Quote:

Originally Posted by KevinVM20
I am unsure how to find the height of the building could someone help?

Here is a sample prob I am given,

Angle 71 Distance 20 Meters

Top

L
l Angle
; in
l box
l
_____________________________71
20
Any potential help appreciated.

Since $tan{\theta}=\frac{o}{a}$, let $\theta=71^\circ$, and let $a=20$, and let $o=$ the side opposite $\theta$ (which is the height of the building).

$\tan{71^\circ}=\frac{o}{20}$

Therefore,

$(20)\tan{71^\circ}=o$

Does that help?

Note that in this problem we didn't have to find any of the other angles to find the height of the building.