Solving an Angle with Trigonometry

In summary, to solve an angle using trigonometry, you need to use the trigonometric functions sine, cosine, and tangent with at least one side length and one angle measurement of the triangle. The process involves setting up an equation and using algebra to solve for the unknown angle. There is a difference between solving a right triangle and any triangle, with the latter requiring the use of the law of sines and/or the law of cosines. The law of sines is used with two angle measurements and one side length or vice versa, while the law of cosines is used when all three side lengths are known or two side lengths and the included angle. Additionally, there are special cases to consider, such as when using the law
  • #1
klm
165
0
edit- nevermind i got it
okay what i figured so far is that the angle i am looking for is 30 degrees, b/c that bottom angle is 45, so the other angle total should be 45. and then i subtracted 15 and got 30. so i am thinking that the component that is suppose to be tangent would be 2cos30=Ay ...would that be correct?
and i have no idea how i am suppose to get the perpendicular one. any help would be greatly appreciated!

Homework Statement


Homework Equations


The Attempt at a Solution

 
Last edited:
Physics news on Phys.org
  • #2
so really the tangent would be 2sin30 ?
 
  • #3


Trigonometry is a powerful tool for solving angles and other geometric problems. In this case, it appears that you are trying to find the value of an unknown angle in a triangle. It is important to remember that in a triangle, the sum of all three angles is always 180 degrees. So, if one angle is known to be 45 degrees, then the other two angles must add up to 135 degrees.

To find the value of the unknown angle, you correctly subtracted 15 degrees from the total of 45 degrees and got 30 degrees. This is a valid approach, but there is another way to solve this problem using trigonometric ratios.

In a right triangle, the tangent of an angle is equal to the length of the side opposite the angle divided by the length of the side adjacent to the angle. In this case, the angle you are trying to find is the one opposite the side with a length of 2, and the adjacent side has a length of Ay. So, using the tangent ratio, we can set up the following equation:

tan 30 = 2/Ay

Solving for Ay, we get Ay = 2/tan 30. Using a calculator, we can find that the value of tan 30 is approximately 0.5774. So, Ay = 2/0.5774 = 3.4641.

To find the perpendicular component, we can use the Pythagorean theorem, which states that in a right triangle, the square of the length of the hypotenuse (the side opposite the right angle) is equal to the sum of the squares of the other two sides. In this case, we know that the hypotenuse has a length of 5, and one of the sides has a length of 2. So, using the Pythagorean theorem, we can set up the following equation:

5^2 = 2^2 + Ay^2

Solving for Ay, we get Ay = √(5^2 - 2^2) = √21 ≈ 4.5826.

So, the two components we were looking for are Ay = 3.4641 and the perpendicular component ≈ 4.5826. I hope this helps!
 

FAQ: Solving an Angle with Trigonometry

How do I solve an angle using trigonometry?

To solve an angle using trigonometry, you need to use the trigonometric functions sine, cosine, and tangent. You will also need to know at least one side length and one angle measurement of the triangle.

What is the process for solving an angle using trigonometry?

The process for solving an angle using trigonometry involves using the trigonometric functions and the given side and angle measurements to set up an equation. Then, you can use algebra to solve for the unknown angle.

What is the difference between solving a right triangle and solving any triangle using trigonometry?

Solving a right triangle using trigonometry involves using the basic trigonometric functions and the Pythagorean theorem. Solving any triangle using trigonometry requires the use of the law of sines and/or the law of cosines, which take into account the relationships between all three sides and angles of a triangle.

When should I use the law of sines versus the law of cosines to solve an angle using trigonometry?

The law of sines is used when you have two angle measurements and one side length, or two side lengths and one angle measurement. The law of cosines is used when you have all three side lengths or two side lengths and the included angle.

Are there any special cases to consider when solving an angle using trigonometry?

Yes, there are a few special cases to consider. When using the law of sines, if the given angle measurement is acute, there will be two possible solutions. If the given angle measurement is obtuse, there will be no solution. When using the law of cosines, if the given angle measurement is obtuse, there will be two possible solutions.

Back
Top