Trigonometry find the opposite side

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    Trigonometry
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Discussion Overview

The discussion revolves around finding the length of the opposite side of a right triangle using trigonometric relationships, specifically focusing on the tangent function and the mnemonic SOH-CAH-TOA. Participants explore different approaches and formulas based on given information, such as the length of the adjacent side and the angle.

Discussion Character

  • Technical explanation
  • Mathematical reasoning
  • Homework-related

Main Points Raised

  • One participant inquires about the correct formula to find the opposite side given the adjacent side and an angle, initially suggesting "opposite = tan degree / adjacent."
  • Another participant corrects this by stating that the correct relationship is "tan(θ) = opposite / adjacent," clarifying the roles of the sides and the angle.
  • A participant provides an example calculation for finding the adjacent side using the opposite side and angle, demonstrating the application of the tangent function.
  • One participant later corrects their earlier statement, stating the correct formula to find the opposite side is "adjacent * tan = opposite."
  • Another participant reiterates the basic formula "tan(θ) = O/A" and explains how to rearrange it to find either the opposite or adjacent side based on known values.

Areas of Agreement / Disagreement

Participants generally agree on the use of the tangent function and the relationships between the sides of the triangle, but there is some confusion regarding the correct application of the formulas, leading to different interpretations of how to find the opposite side.

Contextual Notes

Some participants express uncertainty in their calculations and the application of the formulas, indicating a need for clarity on the relationships between the sides and angles in trigonometric functions.

Pin Head
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Hi,
I'm a bit curious on how do I find the length of the Opposite side of a Right Triangle,
now I have look a Soh Cah Toa, Now say if I know the length of the Adjacent Line and the the angle of the right triangle which formula should I use?

I thought about Toa is this the way I solve for the opposite?

opposite = tan degree / adjacent
 
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Do you understand what the mnemonic SOH-CAH-TOA means?

In response to your question, it's NOT true that "opposite = tan degree / adjacent". The correct formula is tan(##\theta##) = oppposite/adjacent, where ##\theta## is the acute angle you're looking at, opposite is the side opposite to ##\theta##, and adjacent is the side that is between ##\theta## and the right angle.
 
Yes I understand Soh Cah Toa but I am using the equation to find the side of an unknown
side and the formula I'm using is
Example

tan = opposite / adjacent
but I only have the opposite side and the angle so to find the adjacent side I used this formula

24 / tan 42 degrees = 26.654700355900628883443567139963

adjacent side = 26.654700355900628883443567139963

But now the side I want to find is the Opposite side, do I used the same equation but put the angle tan degree in the Opposite side and divide by the adjacent side to find the Opposite side

tan degree / adjacent = Opposite side ?

opposite = ?
 
Hi,
Sorry my mistake The formula I should of used is

adjacent * tan = opposite

example

12 * tan24 = 5.342744223702433967068404367748
 
Pin Head said:
Yes I understand Soh Cah Toa but I am using the equation to find the side of an unknown
side and the formula I'm using is
Example

tan = opposite / adjacent
but I only have the opposite side and the angle so to find the adjacent side I used this formula

24 / tan 42 degrees = 26.654700355900628883443567139963

adjacent side = 26.654700355900628883443567139963

But now the side I want to find is the Opposite side, do I used the same equation but put the angle tan degree in the Opposite side and divide by the adjacent side to find the Opposite side

tan degree / adjacent = Opposite side ?

opposite = ?

It's pretty simple algebra. The basic formula is
tan(θ) = O/A ... (1)

If you know the angle, θ, and the adjacent side A, and you want to find the opposite side O, multiply both sides of the equation above by A.
This gives you O = A*tan(θ)

If you know the angle and the opposite side O, and you want the adjacent side, A, multiply both sides of equation 1 by A, and then divide both sides by tan(θ).

tan(θ) = O/A
A*tan(θ) = O
A = O/tan(θ)
 

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