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Solving for an angle in a right triangle using the trigonometric ratios

Solving for an angle in a right triangle using the trigonometric ratios

In a right triangle, the trigonometric ratios can be used to solve for angles. The primary ratios are:

  1. Sine (sin): The ratio of the length of the opposite side to the length of the hypotenuse. sin(θ)=oppositehypotenuse\sin(\theta) = \frac{\text{opposite}}{\text{hypotenuse}}

  2. Cosine (cos): The ratio of the length of the adjacent side to the length of the hypotenuse. cos(θ)=adjacenthypotenuse\cos(\theta) = \frac{\text{adjacent}}{\text{hypotenuse}}

  3. Tangent (tan): The ratio of the length of the opposite side to the length of the adjacent side. tan(θ)=oppositeadjacent\tan(\theta) = \frac{\text{opposite}}{\text{adjacent}}

To find an angle (θ), you rearrange these formulas and apply the inverse trigonometric functions:

  • θ=sin1(oppositehypotenuse)\theta = \sin^{-1}\left(\frac{\text{opposite}}{\text{hypotenuse}}\right)
  • θ=cos1(adjacenthypotenuse)\theta = \cos^{-1}\left(\frac{\text{adjacent}}{\text{hypotenuse}}\right)
  • θ=tan1(oppositeadjacent)\theta = \tan^{-1}\left(\frac{\text{opposite}}{\text{adjacent}}\right)

By knowing two sides of the triangle, you can use these ratios to calculate the unknown angle.

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