Question

I am a basic trigonometry learner. I have heard till now that trigonometry is all about right triangles.
Please help.

Answer 1

http://assets.openstudy.com/updates/attachments/4fcb45c2e4b0c6963ad4f399-mandy17-1338721738166-71930792159341b491eb279077d0b514.gif

I don't understand how we can get the required side lengths when this isn't a right angled triangle.

Answer 2

I mean, how can even trig have such things when the fundamental is to use right triangles.

Answer 3

I just need to know how it is used in non-right triangles. I need not find the other lengths.

Answer 4

Many different tools.

You have the fundamental Law of Cosines, Law of Sines, and the fact that all the angles of a triangle add up to \(180\) degrees.

Answer 5

I mean that this isn't used in right angled triangles. How can trig be without right triangles? o.O

Answer 6

Trigonometry is a general study of triangles. Only a subset of trigonometry is right triangle trigonometry.

Answer 7

The sine/cosine rules are derived from right angled triangles.
You can see a proof of the sine rule here if you are interested: http://www.youtube.com/watch?v=DsSVxuFh1WA

Answer 8

Get the third angle , Use the Law
\[/\huge \frac{a}{sinA} = \frac{b}{sinB} = \frac{c}{sinC}\]

Answer 9

Hmmm....I see.

Answer 10

Wiki has a nicer definition of trigonometry: "Trigonometry (from Greek trigōnon "triangle" + metron "measure"[1]) is a branch of mathematics that studies triangles and the relationships between their sides and the angles between these sides."

Answer 11

sine law and cosine law are very broad o.O a lot of conditions

Answer 12

I just needed to know how and why it's used in non-right triangles. Thank you :)

Answer 13

You are welcome. :)