hey! can someone please explain trig with obtuse angles? (i really don't get how it works)
Hey! I didn't do General, but I'm using your formula sheet as a guide. Let's look at the following triangle
We denote capital letters as the angle, and small letters as the side. There are a few formulas you need to know
AreaFirst, you need to be able to find the area of this triangle. To do this, we simply apply the formula
Note that the angle, C, needs to be between the two sides a and b. So, in the above triangle, the formula would actually be
You only need to know one angle, and the two sides surrounding that angle, to get the area!
The sine rule states that the ratio of the sine of an angle over the opposite side is the same as the ratio of the sine of any other angle over their opposite sides. On your formula sheet, it is
In our above triangle, it will be
Note that it's all about the ANGLE and it's OPPOSITE side! Here, you can use two known angles and a known side to find other sides, or two known sides and one known angle to find another angle.
Cosine ruleFinally, we have the cosine rule, which is used to find angles or sides given known values. On your formula sheet, the rule is
Give us some example questions we can help you with! It'll be way easier to understand when you're applying it