A Trig Question

Not sure - but I bet they add up to 180

 

18.612 deg
157.727 deg
3.66 deg

using law of Cosines

A² = B² + C² −2(B)(C)cos(angle 1)
B² = A² + C² −2(A)(C)cos(angle 2)
C² = A² + B² −2(A)(B)cos(angle 3)

A,B and C being the lengths of the sides

 

http://www.teacherschoice.com.au/maths_library/trigonometry/solve_trig_sss.htm

 

That works too...

 

I'm too lazy to do it. And it would give me really bad flashbacks.

 

ah yes...me too..too many years since I got my EE. We did all this stuff on a slide rule back then. Boy, I'm dating myself now

 

I love math, but trigonometry is the single worst thing to learn in school. I just can't stand it.

 

Because there is no truth. One answer is as good as another. And I see you're in Canada. Maybe that's it.

 

maybe the prof is trying to throw you off to prove him wrong...I had a circuits analyses prof do that a few times, just to see if we were on our toes...

Math is either right or wrong...if you and I came up with the same answer irrespective of each other, then I would say the prof is wrong

 

I must be a sucker for pain...I loved trig. I hated probability and statistics...I used to call it "unmath". To many variables and unknowns for me to be called "real" math...

 

trig OK. linear algebra--aaaaaaaaahhhhh!

 

Draw a picture of it. But scale it down to centimeters or something. I could do it in AutoCAD if I had AutoCAD at my fingertips, but I'm on my MacBook.

 

http://www.analyzemath.com/Geometry_calculators/cosine_law_calculator.html

Needs Java to work.

 

all angles=180 degrees. 1.6+1.9+0.32=3.82
180 divided by 3.82= 47.1020419blah
47.1 times 0.32=15.08
47.1 times 1.6= 75.4
47.1 times 1.9=89.53

took a quick chance on this,,,any doubts?

 

That won't work - the ratio of the angles is not just the ratio of the sides. Consider the pythagorean triad 3, 4, 5. The side opposite the right angle would be exactly half the perimeter if your method worked; clearly this is not the case.

Given 3 sides of a triangle, you use the cosine rule to work out the biggest angle and then the sine rule to get one of the other two angles. Then get the final angle by subtraction from 180.