Examine the diagram of the roof truss below. Determine the length of TR. Find the angle of elevations.

omgineedhelp123 · Mar 3, 2021

I tried to use trig ratios then realized it wasn’t a right triangle. I can’t figure this out. Please help!

skeeter · Mar 3, 2021

Use the law of cosines to find length of TR, then use the law of sines to determine angle R.

omgineedhelp123 · Mar 3, 2021

skeeter said:
Use the law of cosines to find length of TR, then use the law of sines to determine angle R.

How do I use cosine if I’m not given any SSS or SAS?

skeeter · Mar 4, 2021

look again ... you have SAS

law of cosines ...

[MATH]a^2 = b^2 + c^2 - 2bc\cos{A}[/MATH]
Solving SAS triangles

omgineedhelp123 · Mar 4, 2021

skeeter said:
look again ... you have SAS

law of cosines ...

[MATH]a^2 = b^2 + c^2 - 2bc\cos{A}[/MATH]
Solving SAS triangles

ohhhhh I thought those were two different triangles!!

omgineedhelp123 · Mar 4, 2021

lev888 · Mar 4, 2021

I don't think you are doing operations in the correct order in a)

omgineedhelp123 · Mar 4, 2021

lev888 said:
I don't think you are doing operations in the correct order in a)

How am I supposed to write it then?

lev888 · Mar 4, 2021

omgineedhelp123 said:
How am I supposed to write it then?

It's written correctly, it's the calculation that's wrong. You didn't multiply 2*41*28 by cos(70) before doing subtraction.

omgineedhelp123 · Mar 4, 2021

lev888 said:
It's written correctly, it's the calculation that's wrong. You didn't multiply 2*41*28 by cos(70) before doing subtraction.

OMG THANK YOUUU