Triginomitry

[Juspar Emvan]

Or however the fuck you spell it. Shit, I can't seem to remember the rules, and maths is supposed to be my strong point, don't ask me to spell the fucker.

Anyway, I know the length of the two equal sides of an icosolies(sp - again) triangle, and all the angles. How do I work out the other side?

 

[bluntforcemama]

Trigonometry.


Find the sum of the angles you know and subtract from 180 to get the angle you don't know.

 

[Scabbers]

soh cah toa

soh: sine = opposite/hypotneuse
cah: cosine = adjacent/hypotneuse
toa: tangent = opposite/adjacent

does your calculator have trig functions? If not, there are tables published--I've never looked on line, but all other aspects of human knowledge are, so why not.

 

[Juspar Emvan]

Thanks Scabbers, I knew the anagrams, but couldn't remember how they translated into equations.

Do these work for a non right angle triangle?

 

[Azwed]

Thanks Scabbers, I knew the anagrams, but couldn't remember how they translated into equations.

Do these work for a non right angle triangle?

the sin and cos functions only work for right angle triangles.

 

[morninggirl5]

It works for right triangles only. What you need to do is use the cosine to find the length of the portion of the third side that would be created if you drew a line to be the height of the triangle.


If you know the length of the two equal sides, you probably know their angles as well.

If the triangle is ABC with sides AB and BC eqaul, angles A and C are equal. Cos <A=1/2AC/AB You can use that to find AC.


This would be much easier to do if I could draw you a picture.

 

[Unclebill]

A line bisecting the angle formed by the two equal sides of the isosceles is perpendicular to the side opposite that angle and bisects that side. Use the new angle and the sine function to compute the length of the side (the bisected line) of the new triangle. Then double that value to determine the length of the unknown side of the original triangle.

 

[Unclebill]

Trigonometry

Or how about this: