### Present Remotely

Send the link below via email or IM

• Invited audience members will follow you as you navigate and present
• People invited to a presentation do not need a Prezi account
• This link expires 10 minutes after you close the presentation

Do you really want to delete this prezi?

Neither you, nor the coeditors you shared it with will be able to recover it again.

You can change this under Settings & Account at any time.

# The Law of Sine and Cosine

The equations and examples for law of sine and cosine!
by

## lauren curlee

on 22 May 2015

Report abuse

#### Transcript of The Law of Sine and Cosine

The Laws of Sine and Cosine
Lauren Curlee and Matilda Chidlaw
The Law of Sine
When to use:
Use any 2 fractions
Must have side and angle opposite
Use with NON-right triangles
a
A
b
B
c
C
Ambiguous Case: Law of Sines
Given: Angle, Side, Side
ASS
Example
Example of How to use Law of Sine:
Given:
m < C = 30
ac = 7
cb = 6
The Law of Cosine
When to Use:
Always need 2 sides and the angle they form!
Example of Law of Cosine
c
a
b
B
A
C
30
o
c
A
B
7
6
angle
side
side
7
_____
sin(B)
=
6

____
sin(30)
sin(B) = 7(sin(30))
____
6
That comes out to: m<B = 36
o
But because you were given angle, side, side you need to account for the 2 possible triangles since angle B could change.
30
7
6
* still same triangle according to given information, but angle B has changed.
How to account for 2
nd
triangle
You need to make angle B obtuse, which means you need to take the angle you found before (36) and subtract it from 180.
Now the angles you have are <A = 30 and the new <B, or B' = 144. These angles added together equal 174, which is less than 180.
This means that it is an ambiguous case and the value for C' = 6.

If you were a given a triangle like this and asked to solve you would need to account for both triangles.

Full transcript