## How do you use the law of sines?

How to Use the Law of Sines with a Triangle

- Using the law of sines and the proportion.
- fill in the values that you know. Use the given values, not those that you’ve determined yourself. …
- Use a calculator to determine the values of the sines (in this case, rounded to three decimal places).
- Multiply each side by the denominator under b to solve for that length.

## What is the law of sines and when can it be used?

The law of sines can be used to compute the remaining sides of a triangle when two angles and a side are known—a technique known as triangulation. … The law of sines is one of two trigonometric equations commonly applied to find lengths and angles in scalene triangles, with the other being the law of cosines.

## What is the sine rule equation?

Sine Rule. The Sine Rule can be used in any triangle (not just right-angled triangles) where a side and its opposite angle are known. You will only ever need two parts of the Sine Rule formula, not all three. You will need to know at least one pair of a side with its opposite angle to use the Sine Rule.

## Where is angle of depression?

The angle of depression is the angle between the horizontal line of sight and the line of sight down to an object. For example, if you were standing on top of a hill or a building, looking down at an object, you could measure the angle of depression.

## What is the difference between the law of sines and the law of cosines?

The law of cosines (also called “cosine law”) tells you how to find one side of a triangle if you know the other two sides and the angle between them. The law of sines (i.e. the “sine law”) does not let you do that. … You could use it, for example if you know two sides and the angles opposite those two sides.

## Does law of cosines work for all triangles?

It works on any triangle, not just right triangles. where a and b are the two given sides, C is their included angle, and c is the unknown third side. See figure above.

## Does the law of sines work for right triangles?

The Law of Sines says that in any given triangle, the ratio of any side length to the sine of its opposite angle is the same for all three sides of the triangle. This is true for any triangle, not just right triangles.

## What is the law of cosines used for?

The law of cosines allows us to find angle (or side length) measurements for triangles other than right triangles. The third side in the example given would ONLY = 15 if the angle between the two sides was 90 degrees. In the example in the video, the angle between the two sides is NOT 90 degrees; it’s 87.

## Who discovered the law of sines and cosines?

Johannes von Muller

## Why does the law of sines not always work?

Cases when you can not use the Law of Sines

Since we do not know an opposite side and angle, we cannot employ the formula. Or, just look at it: Remember when you have 2 sides, the angle must be non-included. By the way, we could use the law of cosines to find the length of the side opposite the 115° angle.

## What is the formula for any triangle?

The area of a triangle can be expressed using the lengths of two sides and the sine of the included angle. AreaΔ = ½ ab sin C. You may see this referred to as the SAS formula for the area of a triangle.

## Who invented sine law?

Aryabhata