Angle A when three lenghts are known

Mar 2005
8
0
Angle A when three lengths are known

Hi,

Can anybody tell me the formula for getting an angle A when I have the lengths of the 3 sides of a triangle. Ive forgotten how to do it.

Thanks for the help
 
Last edited:

MathGuru

MHF Hall of Fame
Mar 2005
478
315
Finding Angle A

To find an angle when you have the lengths of the three sides you can use the following formula:

a^2 = b^2 + c^2 - 2(bc)cosA

where a is the length of the side opposite A, and b and c are the lengths of the other sides.

Math Guru
 

vms

Apr 2005
17
0
New Delhi, India
Hi prof

How to post the images like this in the messages


thanx
 

MathMan

MHF Hall of Fame
Mar 2005
63
211
vms said:
Hi prof

How to post the images like this in the messages


thanx
the prof created the image and then uploaded it. If you have an image you want to display you can simply attach it when you create the post