Trig/geometry help (triangles/finding sides)

  • Thread starter PhizKid
  • Start date
In summary, to find the side 'R', we can use the law of sines and the given values of L, theta, and phi to solve for R.
  • #1
PhizKid
477
1

Homework Statement


h83RV.png

Find side 'R'. L = 6.10 meters, theta = 36.9 degrees, and phi = 53.1 degrees.

Homework Equations


Pythagorean Theorem
Similar triangles
Law of Sines
Law of Cosines

The Attempt at a Solution


I don't see any way I can attempt this, I'm very rusty with my trig. We have a known side and a right angle, but I don't see how I can make any other angles (since we only have one side I'm assuming I need to get an angle somewhere
 
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  • #2
PhizKid said:

Homework Statement


h83RV.png

Find side 'R'. L = 6.10 meters, theta = 36.9 degrees, and phi = 53.1 degrees.

Homework Equations


Pythagorean Theorem
Similar triangles
Law of Sines
Law of Cosines

The Attempt at a Solution


I don't see any way I can attempt this, I'm very rusty with my trig. We have a known side and a right angle, but I don't see how I can make any other angles (since we only have one side I'm assuming I need to get an angle somewhere

Draw a vertical line through the right side of the length L (the point on the triangle). The length L will be perpendicular to this line, yes? And now take notice that [itex]\phi[/itex] would be the angle between the vertical and the side of the triangle because of the parallel lines rule (the wall is parallel to the vertical line we constructed).
 
  • #3
law of sines gives

L/sin(phi+theta)=R/cos(phi)
 

1. How do I find the missing side length of a triangle using trigonometry?

To find the missing side length of a triangle using trigonometry, you will need to use one of the trigonometric ratios (sine, cosine, or tangent) depending on the given information. For example, if you have the measure of an angle and the length of the adjacent side, you can use cosine to find the missing side length.

2. Can I use trigonometry to solve any triangle?

Yes, you can use trigonometry to solve any triangle as long as you have enough information. This means you need to know at least three of the angles or side lengths of the triangle.

3. How do I use the Pythagorean theorem to find the missing side length of a right triangle?

To use the Pythagorean theorem to find the missing side length of a right triangle, you will need to know the lengths of the other two sides. Then, you can use the formula a² + b² = c², where a and b are the lengths of the legs and c is the length of the hypotenuse.

4. What is the difference between the sine, cosine, and tangent ratios?

The sine ratio is the ratio of the opposite side to the hypotenuse, the cosine ratio is the ratio of the adjacent side to the hypotenuse, and the tangent ratio is the ratio of the opposite side to the adjacent side in a right triangle. Each ratio can be used to find a missing side length or angle measure in a triangle.

5. Can I use trigonometry to find the area of a triangle?

Yes, you can use trigonometry to find the area of a triangle if you know the lengths of two sides and the included angle. You can use the formula A = 1/2ab sin C, where a and b are the given side lengths and C is the included angle.

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